ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Photosynthesis
  • Springer  (177)
  • Wiley-Blackwell  (2)
  • Elsevier
  • 1990-1994  (179)
  • 1
    Electronic Resource
    Electronic Resource
    Light energy conversion with pheophytina monolayer at the SnO2 optically transparent electrode (1994)
    Springer
    Journal of solution chemistry 23 (1994), S. 223-248 
    Details
    ISSN: 1572-8927
    Keywords: Photosynthesis ; pheophytina ; photoelectrochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The photoelectrochemical, absorption and fluorescence properties of pheophytin a mono- and multilayers, deposited on optically transparent tin oxide electrodes and quartz slides were investigated. Spectra of photocurrents coincided with the absorption spectra of photosynthetic pigment in monolayers at the SnO2/solution interfaces. The anodic and cathodic photocurrents were measured at various electrode potentials. Effects of pH, electrode potentials, and concentration of redox reagents on the conversion of solar energy in monolayers on optically transparent electrodes are discussed. The absorption and fluorescence spectral characteristics, and fluorescence lifetime measurements of pheophytina in monolayers and thin films are also discussed in view of the aggregation properties of the photosynthetic pigment. The thermodynamics of adsorption of large amphiphilic compounds at the interface between two immiscible liquids is considered. The adsorption behavior of pheophytin a dissolved in different solvents is investigated. The thermodynamic parameters of pheophytin a adsorption at octane/water and benzene/water interfaces were determined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00973548
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Photosynthetic capacity and nitrogen partitioning among species in the canopy of a herbaceous plant community (1994)
    Springer
    Oecologia 100 (1994), S. 203-212 
    Details
    ISSN: 1432-1939
    Keywords: Canopy structure ; Nitrogen use efficiency Photon absorption ; Photosynthesis ; Species coexistence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Partitioning of nitrogen among species was determined in a stand of a tall herbaceous community. Total amount of nitrogen in the aboveground biomass was 261 mmol N m−2, of which 92% was in three dominant species (Phragmites, Calamagrostis and Carex) and the rest was in the other eight subordinate species. Higher nitrogen concentrations per unit leaf area (n L) with increasing photosynthetically active photon flux density (PPFD) were observed in all species except for three short species. The changes in n L within species were mainly explained by the different nitrogen concentrations per unit leaf mass, while the differences in n L between species were explained by the different SLM (leaf mass per unit leaf area). Photon absorption per unit leaf nitrogen (Φ N ) was determined for each species. If photosynthetic activity was proportional to photon absorption, Φ N should indicate in situ PNUE (photosynthetic nitrogen use efficiency). High Φ N of Calamagrostis (dominant) resulted from high photon absorption per unit leaf area (Φ area ), whereas high Φ N of Scutellaria (subordinate) resulted from low n L although its Φ area was low. Species with cylinder-like “leaves” (Juncus and Equisetum) had low Φ N , which resulted from their high n L. Light-saturated CO2 exchange rates per unit leaf area (CER) and per unit leaf nitrogen (potential PNUE) were determined in seven species. Species with high CER and high n L (Phragmites, Carex and Juncus) had low potential PNUE, while species with low CER and low n L showed high potential PNUE. NUE (ratio of dry mass production to nitrogen uptake) was approximated as a reciprocal of plant nitrogen concentration. In most species, three measures of nitrogen use efficiency (NUE, Φ N and potential PNUE) showed strong conformity. Nitrogen use efficiency was high in Calamagrostis and Scutellaria, intermediate in Phragmites and relatively low in Carex. Nitrogen use efficiency of subordinate species was as high as or even higher than that of dominant species, which suggests that growth is co-limited by light and nitrogen in the subordinate species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00316946
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Production and diurnal utilization of assimilates in leaves of spinach (Spinacia oleracea L.) and barley (Hordeum vulgare L.) (1994)
    Springer
    Planta 192 (1994), S. 497-501 
    Details
    ISSN: 1432-2048
    Keywords: Amino acid ; Hordeum (leaves) ; Phloem transport ; Photosynthesis ; Spinacia (leaves) ; Sucrose (translocation)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Rates of CO2 fixation during the light period and the rates of CO2 release during the night period were measured using mature leaves from 39- to 49-d-old spinach (Spinacia oleracea L., US Hybrid 424; grown in 9 h light, 15 h darkness, daily) and mature leaves from 21-d-old barley (Hordeum vulgare L., cv. Apex; grown in 14 h light, 10 h darkness, daily). At certain times during the light and dark periods leaves were harvested for assay of their contents of soluble carbohydrates, starch, malate and the various amino acids. Evaluation of the results of these measurements shows that in spinach and barley leaves 46% and 26%, respectively, of the carbon assimilated during the light period is deposited in the leaves for export during the night period. Taking into account the carbon consumption in the source leaves by dark respiration, it is evaluated that rates of assimilate export during the light period from spinach and barley leaves [38 and 42 μatom C · (mg Chl)−1 · h−1] are reduced in the dark period to 16 μatom C · (mg Chl)−1 · h−1 in both species. The calculated C/N ratios of the photoassimilates exported during the dark period were 0.029 and 0.015 for spinach and barley leaves, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00203587
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Fructose 2,6-bisphosphate levels in mature leaves of tobacco (Nicotiana tabacum) and potato (Solanum tuberosum) (1994)
    Springer
    Planta 193 (1994), S. 16-20 
    Details
    ISSN: 1432-2048
    Keywords: Fructose 2,6-bisphosphate ; Photosynthesis ; Nicotiana ; Solanum ; Starch ; Sucrose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Here we show that fructose 2,6-bisphosphate cannot be reliably measured in mature leaves of tobacco (Nicotiana tabacum L.), potato (Solanum tuberosum L.), or stinging nettle (Urtica dioica L.) using conventional extraction techniques, since the recoveries of fructose 2,6-bisphosphate added during extraction are poor. However, fructose 2,6-bisphosphate could be extracted by boiling leaves in ethanol and aqueous buffer. Evidence for the reliability of this technique is provided by high recovery measurements of fructose 2,6-bisphosphate added to the leaves before extraction. This extraction method was used to measure changes in the level of fructose 2,6-bisphosphate throughout the photoperiod in tobacco and potato leaves. These changes are compared with the rate of accumulation of sucrose and starch in the leaf samples. Variations in the levels of fructose 2,6-bisphosphate, and the relationship between this metabolite and sucrose and starch accumulation in these leaves during the photoperiod are similar to the pattern observed in leaves of other plant species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00191601
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Relationships among violaxanthin deepoxidation, thylakoid membrane conformation, and nonphotochemical chlorophyll fluorescence quenching in leaves of cotton (Gossypium hirsutum L.) (1994)
    Springer
    Planta 193 (1994), S. 238-246 
    Details
    ISSN: 1432-2048
    Keywords: Chlorophyll fluorescence quenching ; Energy dissipation ; Gossypium ; Light scattering changes ; Photosynthesis ; Xanthophyll cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The kinetics and temperature dependencies of development and relaxation of light-induced absorbance changes caused by deepoxidation of violaxanthin to antheraxanthin and zeaxanthin (ΔZ; peak at 506 nm) and by light scattering (ΔS; peak around 540 nm) as well as of nonphotochemical quenching of chlorophyll fluorescence (NPQ) were followed in cotton leaves. Measurements were made in the absence and the presence of dithiothreitol (DTT), an inhibitor of violaxanthin deepoxidase. The amount of NPQ was calculated from the Stern-Volmer equation. A procedure was developed to correct gross AS (ΔSg) for absorbance changes around 540 nm that are due to a spectral overlap with ΔZ. This protocol isolated the component which is caused by light-scattering changes alone (ΔSn). In control leaves, the kinetics and temperature dependence of the initial rate of rise in ΔSn that takes place upon illumination, closely matched that of ΔZ. Application of DTT to leaves, containing little zeaxanthin or antheraxanthin, strongly inhibited both ΔSn and NPQ, but DTT had no inhibitory effect in leaves in which these xanthophylls had already been preformed, showing that the effect of DTT on ΔAn and NPQ results solely from the inhibition of violaxanthin deepoxidation. The rates and maximum extents of ΔSn and NPQ therefore depend on the amount of zeaxanthin (and/or antheraxanthin) present in the leaf. In contrast to the situation during induction, relaxation of ΔZ upon darkening was much slower than the relaxation of ΔSn and NPQ. The relaxation of ΔSn and NPQ showed quantitatively similar kinetics and temperature dependencies (Q10=2.4). These results are consistent with the following hypotheses: The increase in lumen-proton concentration resulting from thylakoid membrane energization causes deepoxidation of violaxanthin to antheraxanthin and zeaxanthin. The presence of these xanthophylls is not sufficient to cause ΔSn or NPQ but, together with an increased lumen-proton concentration, these xanthophylls cause a conformational change, reflected by ΔSn. The conformational change facilititates nonradiative energy dissipation, thereby causing NPQ. Membrane energization is prerequisite to conformational changes in the thylakoid membrane and resultant nonradiative energy dissipation but the capacity for such changes in intact leaves is quite limited unless zeaxanthin (and/or antheraxanthin) is present in the membrane. The sustained ΔSn and NPQ levels that remain after darkening may be attributable to a sustained high lumen-proton concentration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00192536
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Effect of antisense repression of the chloroplast triose-phosphate translocator on photosynthetic metabolism in transgenic potato plants (1994)
    Springer
    Planta 193 (1994), S. 174-180 
    Details
    ISSN: 1432-2048
    Keywords: Antisense repression ; Photosynthesis ; Solanum ; Starch synthesis ; Triose phosphate translocator
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The introduction of an antisense DNA into transgenic potato (Solanum tuberosum L.) plants decreased the expression of the chloroplast triose-phosphate translocator and lowered its activity by 20–30%. With plants propagated from tubers, the effect of the transformation on photosynthetic metabolism was analysed by measuring photosynthesis, the formation of leaf starch, and the total and subcellular metabolite contents in leaves. Although the transformants, in contrast to those propagated from cell cultures, did not differ from the wild-type plants in respect to rates of photosynthesis, plant appearance, growth and tuber production, their photosynthetic metabolism was found to be severely affected. The results show that the decrease in activity of the triose-phosphate translocator in the transformants caused a fourfold increase in the level of 3-phosphoglycerate and a corresponding decrease in inorganic phosphate in the stromal compartment, resulting in a large increase in the synthesis of starch. Whereas during a 12-h day period wild-type plants deposited 43% of their CO2 assimilate into starch, this value rose to 61–89% in the transformants. In contrast to the wild-type plants, where the rate of assimilate export from the leaves during the night period was about 75% of that during the day, the export rate from leaves of transformants appeared to be much higher during the night than during the day. As the mobilisation of starch occurs in part hydrolytically, resulting in the formation of glucose, the triose-phosphate translocator loses its exclusive function in the export of carbohydrates from the chloroplasts when the photoassimilates are temporarily deposited as starch. It appears that by directing the CO2 assimilates mainly into starch, the transformants compensate for the deficiency in triose-phosphate translocator activity in such a way that the productivity of the plants is not affected by the transformation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00192527
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Mechanism of photosystem-I photoinhibition in leaves of Cucumis sativus L. (1994)
    Springer
    Planta 194 (1994), S. 287-293 
    Details
    ISSN: 1432-2048
    Keywords: Chilling stress ; Cucumis (photoinhibition) ; Photoinhibition ; Photosynthesis ; Photosystem I ; Subunit protein degradation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract It was recently shown that the site of photoinhibition in leaves of Cucumis sativus L. at low temperatures is Photosystem I (PSI), not PSII (I. Terashima et al. 1994, Planta 193, 300–306). In the present study, the mechanisms of this PSI photoinhibition in vivo were examined. By lowering the photon flux density during the photoinhibitory treatment of leaves at 4°C for 5 h to less than 100 μmol·m−2s−1, we were able to separate the steps of the destruction of the electron-transfer components. Although P-700, the reaction-center chlorophyll, was almost intact in this low-light treatment, the quantum yield of the electron transfer through PSI and photochemically induced absorption change at 701 nm were markedly inhibited. This, along with the results from the measurements of the light-induced absorption changes in the presence of various concentrations of methyl viologen, an artificial electron acceptor, indicates that the component on the acceptor side of the PSI, A1 or Fx, is the first site of inactivation. When the photon flux density during the treatment was increased to 220 μmol·m−2s−1, the destruction of P-700 itself was also observed. Furthermore, the partial degradation of the chlorophyll-binding large subunits was observed in photoinhibited leaves. This degradation of the subunits was not detected when the treatment was carried out under nitrogen atmosphere, the condition in which the electron transfer is not inhibited. Thus, the photoinhibitory processes in the reaction center of PSI go through three steps, the inactivation of the acceptor side, the destruction of the reaction-center chlorophyll and the degradation of the reaction center subunit(s). The similarities and the differences between the mechanisms of PSI photoinhibition and those of PSII photoinhibition are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00196400
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Adenine nucleotides and the xanthophyll cycle in leaves (1994)
    Springer
    Planta 192 (1994), S. 526-536 
    Details
    ISSN: 1432-2048
    Keywords: Adenylate energy charge ; Adenylate kinase equilibrium ; Aegialitis ; Gossypium ; Photosynthesis ; Stress (low temperature, low CO2) ; Xanthophyll cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of varying the steady-state rate of non-cyclic photosynthetic electron transport on the leaf adenylate energy charge and the epoxidation state of the xanthophyll-cycle pigments were determined in leaves of cotton (Gossypium hirsutum L.) and the mangrove (Aegialitis annulata R.Br.). Different photosynthetic rates were obtained by varying the intercellular CO2 concentration and/or the leaf temperature, and in some cases, by changing the leaf conductance to CO2 diffusion. Also determined were the effects of these treatments on the changes in the adenylate energy charge and the epoxidation state of the xanthophyll-cycle pigments that occur after darkening of the leaves. The leaf adenylate pool remained close to equilibrium with the adenylate kinase both in the light at steady state and during dark relaxation. The adenylate energy charge increased as the photosynthetic rate decreased and maximal levels were obtained when CO2 assimilation and, therefore, non-cyclic electron flow were maximally inhibited. This implies that, in nature, photophosphorylation may provide energy needed for ion-pumping and biosynthetic and repair processes, even under stress conditions that severely restrict or prevent photosynthetic gas exchange. High levels of de-epoxidized violaxanthin in the light did not necessarily indicate or depend on a high adenylate energy charge. Dithiothreitol, an inhibitor of the violaxanthin de-epoxidase a nd ascorbate peroxidase, did not inhibit the adenylate energy charge in the light. Thus we conclude that coupled electron transport during inhibited CO2 fixation was not driven by a dithiothreitol-sensitive Mehler ascorbate-peroxidase reaction. The changes in the adenylate energy charge and xanthophyll re-epoxidation that follow when leaves were darkened are strongly affected by the preceding photosynthetic rate. Postillumination fluctuations in adenylate energy charge, both at 15 ° and 27 °C, were most pronounced when the preceding photosynthetic rate was minimal and least pronounced when this rate was maximal. Temperature had a considerably greater influence in the dark on xanthophyll re-epoxidation than on the pattern of adenylate relaxation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00203591
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    A membrane-located polypeptide ofUlva sp. which may be involved in HCO 3 - uptake is recognized by antibodies raised against the human red-blood-cell anion-exchange protein (1994)
    Springer
    Planta 194 (1994), S. 247-249 
    Details
    ISSN: 1432-2048
    Keywords: Anion exchange(r) ; Bicarbonate uptake ; Photosynthesis ; Ulva
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Polypeptides present in a membrane fraction of the marine macroalgaUlva sp. were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and tested for cross-reactivity with antibodies raised against the human red-blood-cell anion exchanger (AE1). A polypeptide of ca. 95 kDa was identified with a monoclonal, as well as two polyclonal (one against the C-terminus and one against the whole protein) antibodies, indicating that it shares homologous domains with AE1. These findings complement an earlier study which indicated that a plasmalemma-bound, disulfonic stilbenesensitive, protein was functionally involved in HCO 3 - transport into the photosynthesizing cells ofUlva (Z. Drechsler et al. 1993, Planta191, 34–40). It is thus suggested here that a similar protein has evolved, and has been conserved, in marine photosynthetic organisms and mammalian red blood cells for the purpose of HCO 3 - transport.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01101684
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    A membrane-located polypeptide of Ulva sp. which may be involved in HCO 3 - uptake is recognized by antibodies raised against the human red-blood-cell anion-exchange protein (1994)
    Springer
    Planta 194 (1994), S. 247-249 
    Details
    ISSN: 1432-2048
    Keywords: Anion exchange(r) ; Bicarbonate uptake ; Photosynthesis ; Ulva
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Polypeptides present in a membrane fraction of the marine macroalga Ulva sp. were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and tested for cross-reactivity with antibodies raised against the human red-blood-cell anion exchanger (AE1). A polypeptide of ca. 95 kDa was identified with a monoclonal, as well as two polyclonal (one against the C-terminus and one against the whole protein) antibodies, indicating that it shares homologous domains with AE1. These findings complement an earlier study which indicated that a plasmalemma-bound, disulfonic stilbenesensitive, protein was functionally involved in HCO 3 - transport into the photosynthesizing cells of Ulva (Z. Drechsler et al. 1993, Planta 191, 34–40). It is thus suggested here that a similar protein has evolved, and has been conserved, in marine photosynthetic organisms and mammalian red blood cells for the purpose of HCO 3 - transport.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00196394
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    The induction of the CO2-concentrating mechanism is correlated with the formation of the starch sheath around the pyrenoid of Chlamydomonas reinhardtii (1994)
    Springer
    Planta 195 (1994), S. 210-216 
    Details
    ISSN: 1432-2048
    Keywords: Chlamydomonas ; Carbon-dioxide-concentrating mechanism ; Photosynthesis ; Pyrenoid ; Starch
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The pyrenoid is a prominent proteinaceous structure found in the stroma of the chloroplast in unicellular eukaryotic algae, most multicellular algae, and some hornworts. The pyrenoid contains the enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase and is sometimes surrounded by a carbohydrate sheath. We have observed in the unicellular green alga Chlamydomonas reinhardtii Dangeard that the pyrenoid starch sheath is formed rapidly in response to a decrease in the CO2 concentration in the environment. This formation of the starch sheath occurs coincidentally with the induction of the CO2-concentrating mechanism. Pyrenoid starch-sheath formation is partly inhibited by the presence of acetate in the growth medium under light and low-CO2 conditions. These growth conditions also partly inhibit the induction of the CO2-concentrating mechanism. When cells are grown with acetate in the dark, the CO2-concentrating mechanism is not induced and the pyrenoid starch sheath is not formed even though there is a large accumulation of starch in the chloroplast stroma. These observations indicate that pyrenoid starch-sheath formation correlates with induction of the CO2-concentrating mechanism under low-CO2 conditions. We suggest that this ultrastructural reorganization under lowCO2 conditions plays a role in the CO2-concentrating mechanism C. reinhardtii as well as in other eukaryotic algae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00199681
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Mid-season gas exchange of an alpine grassland under elevated CO2 (1994)
    Springer
    Oecologia 98 (1994), S. 429-435 
    Details
    ISSN: 1432-1939
    Keywords: Climate change ; Carbon dioxide ; Altitude ; Photosynthesis ; Water loss
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ecosystem net CO2 uptake, evapotranspiration (ET) and night-time CO2 efflux were measured in an alpine grassland dominated by Carex curvula, treated with doubled ambient partial pressure of CO2 via open-top chambers. One quarter of the plots were treated with mineral nutrients to simulate the effect of lowland nitrogen deposition rates. Depending upon fertilizer supply, ecosystem net CO2 uptake per ground area in full sunlight (NCEmax) was 41–81% higher in open-top chambers supplied with doubled ambient partial pressure (p a) of CO2 than in plots receiving ambient CO2. Short-term reversals of the CO2 level suggest that the extent of downward adjustment of canopy photosynthesis under elevated CO2 was 30–40%. ET tended to decline, while water use efficiency (WUE), expressed as the NCEmax:ET ratio, increased more than twofold under elevated CO2. Night-time ecosystem CO2 efflux did not respond to changes in CO2 p a. NCEmax and night-time CO2 efflux were more responsive to mineral fertilizer than the doubling of CO2. This suggests that in these alpine plant communities, atmospheric nutrient input may induce equal or greater effects on gas exchange than increased CO2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00324233
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Above- and below-ground environmental influences on leaf conductance ofCeanothus thyrsiflorus growing in a chaparral environment: drought response and the role of abscisic acid (1994)
    Springer
    Oecologia 99 (1994), S. 306-314 
    Details
    ISSN: 1432-1939
    Keywords: Abscisic acid ; Chaparral ; Ceanothus thyrsiflorus ; Conductance ; Photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Small shrubs ofCeanothus thyrsiflorus were grown in 19-1 pots irrigated under natural conditions in a chaparral region of Southern California and then subjected to soil drying. Characteristics of leaf gas exchange, leaf water potential, and concentrations of the stress hormone abscisic acid in the xylem sap, ABAxyl, were determined at various stages of drought. Diurnal changes in conductance were strongly correlated with leaf net photosynthesis rate, which provides an effective, integrative predictor of above-ground climate effects on conductance. In drought conditions, ABAxyl concentration increased. Increases in the concentration range of 50–500 nmol/l appeared to induce stomatal closure, restricting water loss and carbon dioxide uptake. When the momentary water potential is related to ABAxyl, ABA appeared to increase significantly only after a threshold of approximately −1.5 MPa was exceeded. At less negative water potentials, large variation in ABAxyl in the 50–1000 nmol/l range occurred for all water-potential values, because ABAxyl remains relatively constant over diurnal courses as water potentials decrease and then recover. When the water potential became more negative than −1.5 MPa, ABAxyl concentrations occurred between approximately 500 and 10 000 nmol/l and even greater in isolated cases. An approximately linear relationship is recognizable between ABAxyl and momentary water potential in this range because in plants under drought conditions, ABAxyl increases during the course of the day as water potential decreases. Increases in ABAxyl in the high concentration range were associated with relatively minor additional restrictions in gas exchange, but they might contribute to improved water use efficiency and explain diurnal changes in the potential for stomatal opening that have been observed in Mediterranean sclerophyllous species. When we examined long-term seasonal change in the response of irrigated plants, changes in average daily temperature greater than 10°C occurred (also associated with shifts in relative humidity and radiation input), which apparently led to small changes in predawn water potential in the −0.1 to −0.7 MPa range. Increases in ABAxyl occurred that were in turn negatively correlated with daily maximum leaf conductance. Thus, chaparral shrubs under non-drought conditions seem to sense even small changes in environmental conditions, in our opinion most probably due to initial drying of the uppermost soil and synthesis of ABA in the shallow roots. The results support the hypothesis that information of photosynthesis rate and predawn water potential may be used as primary variables to predict canopy conductance of Mediterranean sclerophyll shrub vegetation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00627743
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Long term effects of naturally elevated CO2 on mediterranean grassland and forest trees (1994)
    Springer
    Oecologia 99 (1994), S. 343-351 
    Details
    ISSN: 1432-1939
    Keywords: Carbohydrates ; Global change ; Natural CO2 springs ; Leaf nitrogen ; Photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We investigated the carbon supply status in species-rich mediterranean plant communities growing in a bowl-shaped 1-ha “CO2 spring” area near Sienna, Italy. A geothermic “lime-kiln” has provided these communities, for as long as historical records are available, with pure CO2 that mixes with ambient air at canopy level to daytime means of 500–1000 ppm CO2. Immediately outside the spring area similar plant communities are growing on similar substrate, and in the same climate, but under ca. 355 ppm CO2. We found no evidence that plants in the CO2 spring area grow faster, flower earlier or become larger. However, we found very large differences in tissue quality among the 40 species studied inside and outside the spring area. Depending on weather conditions, the mean concentration of total non-structural carbohydrates (TNC, sugars and starch) in leaves of herbaceous plants was 38–47% higher in the spring area. Fast growing ruderals growing on garden soil inside and outside the spring area show the same response. Among trees, leaves of the deciduousQuercus pubscens contain twice as much TNC inside as outside the vent area, whereas evergreenQ. ilex leaves show no significant difference. TNC levels in branch wood paralleled leaf values. TNC in shade leaves was also higher. Elevated CO2 had no effect on the sugar fraction, therefore differences in TNC are due to starch accumulation. Leaf nitrogen concentration decreases under elevated CO2. These observations suggest that the commonly reported TNC accumulation and N depletion in leaves growing under elevated CO2 are not restricted to the artificial conditions of short-term CO2 enrichment experiments but persist over very long periods. Such an alteration of tissue composition can be expected to occur in other plant communities also if atmospheric CO2 levels continue to rise. Effects on food webs and nutrient cycling are likely.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00627748
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Photosynthesis-nitrogen relations in Amazonian tree species (1994)
    Springer
    Oecologia 97 (1994), S. 73-81 
    Details
    ISSN: 1432-1939
    Keywords: Specific leaf area ; Rain forests ; Photosynthesis ; Nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The relationships between leaf nitrogen (N), specific leaf area (SLA) (an inverse index of leaf “thickness” or “density”), and photosynthetic capacity (Amax) were studied in 23 Amazonian tree species to characterize scaling in these properties among natural populations of leaves of different ages and light microenvironments, and to examine how variation within species in N and SLA can influence the expression of the Amax-to-N relationship on mass versus area bases. The slope of the Amax-N relationship, change in A per change in N (μmol CO2 gN-1 s-1), was consistently greater, by as much as 300%, when both measures were expressed on mass rather than area bases. The x-intercept of this relationship (N-compensation point) was generally positive on a mass but not an area basis. In this paper we address the causes and implications of such differences. Significant linear relationships (p〈0.05) between mass-based leaf N (Nmass) and SLA were observed in 12 species and all 23 regressions had positive slopes. In 13 species, mass-based Amax (Amass) was positively related (p〈0.05) with SLA. These patterns reflect the concurrent decline in Nmass and SLA with increasing leaf age. Significant (p〈0.05) relationships between area-based leaf N (Narea) and SLA were observed in 18 species. In this case, all relationships had negative slopes. Taken collectively, and consistent in all species, as SLA decreased (leaves become “thicker”) across increasing leaf age and light gradients, Nmass also decreased, but proportionally more slowly, such that Narea increased. Due to the linear dependence of Amass on Nmass and a negative 4-intercept, “thicker” leaves (low SLA) therefore tend, on average, to have lower Nmass and Amass but higher Narea than “thinner” leaves. This tendency towards decreasing Amass with increasing Narea, resulting in a lower slope of the Amax-N relationship on an area than mass basis in 16 of 17 species where both were significant. For the sole species exception (higher area than mass-based slope) variation in Narea was related to variation in Nmass and not in SLA, and thus, these data are also consistent with this explanation. The relations between N, SLA and Amax explain how the rate of change in Amax per change in N can vary three-fold depending on whether a mass or area mode of expression is used.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00317910
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Relationship of aluminium and calcium to net CO2 exchange among diverse Scots pine provenances under pollution stress in Poland (1994)
    Springer
    Oecologia 97 (1994), S. 82-92 
    Details
    ISSN: 1432-1939
    Keywords: Photosynthesis ; Respiration ; Pinus sylvestris ; Pinus nigra ; Betula pubescens
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Light-saturated net photosynthesis (Asat), dark respiration (RD), and foliar nutrient content of eight European Scots pine (Pinus sylvestris L.) provenances were measured at experimental sites in western Poland. Two-year-old seedlings were planted in 1984 at two sites with similar soils in areas of contrasting air pollution. One site was near a point source of SO2 and other pollutants, and another 12 km to the southeast in an area free of acute air pollution was treated as a control. The eight provenances were from a large north-tosouth latitudinal range (60 to 43° N). At the heavily polluted site Scots pine trees exhibited lower growth rates and crown dieback and deformation. Soil pH, Ca and Mg were at least 10 times lower, and Al 10 times higher at the polluted than the control site. In 1991, concentrations of Al, P, Ca, S, Mn, Fe, and Zn in oneyear old Scots pine foliage were higher and Mg lower at the polluted than control site. At both sites foliar Mg levels were within the range considered deficient (≤0.6 mg g-1), and at the polluted site, Al concentrations were very high (670 to 880 μg g-1). In all provenances, RD of one-year-old needles was higher (by 22% on average) and Asat was lower (by 37% on average) at the polluted than the control site. The ratio of Asat: RD was half as great in all provenances at the polluted (4 to 6) than control site (8 to 11). Provenances of southern origin had greater increases in RD and water-use efficiency at the polluted site than other provenances. Within the polluted site alone, or across both sites, Asat in Scots pine was negatively correlated to the Al: Ca ratio (p〈0.001, r=−0.93). Across sites RD increased with needle N and Al (multiple regression, p〈0.001). The data suggest that at the polluted site there is excessive soil Al and deficient Mg availability, low needle Mg and high Al concentrations and high Al: Ca ratios, and that these have resulted in reduced photosynthetic capacity and increased respiration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00317911
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Photosynthesis-nitrogen relations in Amazonian tree species (1994)
    Springer
    Oecologia 97 (1994), S. 62-72 
    Details
    ISSN: 1432-1939
    Keywords: Amazon ; Rain forests ; Leaf life-span ; Photosynthesis ; Nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Among species, photosynthetic capacity (Amax) is usually related to leaf nitrogen content (N), but variation in the species-specific relationship is not well understood. To address this issue, we studied Amax-N relationships in 23 species in adjacent Amazonian communities differentially limited by nitrogen (N), phosphorus (P), and/or other mineral nutrients. Five species were studied in each of three late successional forest types (Tierra Firme, Caatinga and Bana) and eight species were studied on disturbed sites (cultivated and early secondary successional Tierra Firme plots). Amax expressed on a mass basis (Amass) was correlated (p〈0.05) with Nmass in 17 of 23 species, and Amax on an area basis (Aarea) was correlated (p〈0.05) with Narea in 21 of 23 species. The slopes of Amax-N relationships were greater and intercepts lower for disturbance adapted early successional species than for late successional species. On a mass basis, the Amax-N slope averaged ≈15 μmol CO2 [g N]-1 s-1 for 7 early secondary successional species and ≈4 μmol CO2 [g N]-1 s-1 for 15 late successional species, respectively. Species from disturbed sites had shorter leaf life-span and greater specific leaf area (SLA) than late successional species. Across all 23 species, the slope of the Amass-Nmass relationship was related (p〈0.001) positively to SLA (r2=0.70) and negatively to leaf life-span (r2=0.78) and temporal niche during secondary succession (years since cutting-and-burning, r2=0.90). Thus, disturbance adapted early successional species display a set of traits (short leaf life-span, high SLA and Amax and a steep slope of Amax-N) conducive to resource acquisition and rapid growth in their high resource regeneration niches. The significance and form of the Amax-N relationship were associated with the relative nutrient limitations in the three late successional communities. At species and community levels, Amax was more highly dependent on N in the N-limited Caatinga than in the P-and N-limited Bana and least in the P-and Ca-limited Tierra Firme on oxisol-and differences among these three communities in their massbased Amax-N slope reflects this pattern (6.0, 2.4, and 0.7 μmol CO2 [g N]-1 s-1, respectively). Among all 23 species, the estimated leaf Nmass needed to reach compensation (net photosynthesis ≈ zero) was positively related to the Amass-Nmass slope and to dark respiration rates and negatively related to leaf life-span. Variation among species in the Amax-N slope was well correlated with potential photosynthetic N use efficiency, Amax per unit leaf N. The dependence of Amax on N and the form of the relationship vary among Amazonian species and communities, consistent with both relative availabilities of N, P, and other mineral nutrients, and with intrinsic ecophysiological characteristics of species adapted to habitats of varying resource availability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00317909
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Shoot growth dynamics and photosynthetic response to increased nitrogen availability in the alpine willow Salix glauca (1994)
    Springer
    Oecologia 97 (1994), S. 93-99 
    Details
    ISSN: 1432-1939
    Keywords: Alpine ecosystem ; Biomass allocation ; Nitrogen-use efficiency ; Photosynthesis ; Salix glauca
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Plants subjected to increases in the supply of resource(s) limiting growth may allocate more of those resources to existing leaves, increasing photosynthetic capacity, and/or to production of more leaves, increasing whole-plant photosynthesis. The responses of three populations of the alpine willow, Salix glauca, growing along an alpine topographic sequence representing a gradient in soil moisture and organic matter, and thus potential N supply, to N amendments, were measured over two growing seasons, to elucidate patterns of leaf versus shoot photosynthetic responses. Leaf-(foliar N, photosynthesis rates, photosynthetic N-use efficiency) and shoot-(leaf area per shoot, number of leaves per shoot, stem weight, N resorption efficiency) level measurements were made to examine the spatial and temporal variation in these potential responses to increased N availability. The predominant response of the willows to N fertilization was at the shoot-level, by production of greater leaf area per shoot. Greater leaf area occurred due to production of larger leaves in both years of the experiment and to production of more leaves during the second year of fertilization treatment. Significant leaflevel photosynthetic response occurred only during the first year of treatment, and only in the dry meadow population. Variation in photosynthesis rates was related more to variation in stomatal conductance than to foliar N concentration. Stomatal conductance in turn was significantly related to N fertilization. Differences among the populations in photosynthesis, foliar N, leaf production, and responses to N fertilization indicate N availability may be lowest in the dry meadow population, and highest in the ridge population. This result is contrary to the hypothesis that a gradient of plant available N corresponds with a snowpack/topographic gradient.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00317912
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Water relations, gas exchange, and growth of resprouts and mature plant shoots of Arbutus unedo L. and Quercus ilex L. (1994)
    Springer
    Oecologia 98 (1994), S. 201-211 
    Details
    ISSN: 1432-1939
    Keywords: Growth ; Photosynthesis ; Resprouts ; Water relations ; Sclerophyll shrubs and trees
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Resprout and mature plant shoot growth, leaf water status and gas exchange behavior, tissue nutrient content, flowering, and production were studied for co-occurring shallow-rooted (Arbutus unedo L.) and deeprooted (Quercus ilex L.) Mediterranean tree species at the Collserola Natural Park in Northeast Spain Resprouts showed higher growth rates than mature plant shoots. During fall, no differences in eco-physiological performance of leaves were found, but mobilization of carbohydrates from burls strongly stimulated growth of fall resprouts compared to spring resprouts, despite low exposed leaf area of the fall shoots. During summer drought, resprouts exhibited improved water status and carbon fixation compared to mature plant shoots. Shoot growth of Q. ilex was apparently extended due to deep rooting so that initial slower growth during spring and early summer as compared to A. unedo was compensated. Tissue nutrient contents varied only slightly and are postulated to be of minor importance in controlling rate of shoot growth, perhaps due to the relatively fertile soil of the site. Fall flowering appeared to inhibit fall shoot growth in A. unedo, but did not occur in Q. ilex. The results demonstrate that comparative examinations utilizing vegetation elements with differing morphological and physiological adaptations can be used to analyze relatively complex phenomena related to resprouting behavior. The studies provide an important multi-dimensional background framework for further studies of resprouting in the European Mediterranean region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00341473
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    Compensatory responses of CO2 exchange and biomass allocation and their effects on the relative growth rate of ponderosa pine in different CO2 and temperature regimes (1994)
    Springer
    Oecologia 98 (1994), S. 159-166 
    Details
    ISSN: 1432-1939
    Keywords: Biomass allocation ; Climate change CO2 enhancement ; Photosynthesis ; Relative growth rate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Increases in the concentration of atmospheric carbon dioxide may have a fertilizing effect on plant growth by increasing photosynthetic rates and therefore may offset potential growth decreases caused by the stress associated with higher temperatures and lower precipitation. However, plant growth is determined both by rates of net photosynthesis and by proportional allocation of fixed carbon to autotrophic tissue and heterotrophic tissue. Although CO2 fertilization may enhance growth by increasing leaf-level assimilation rates, reallocation of biomass from leaves to stems and roots in response to higher concentrations of CO2 and higher temperatures may reduce whole-plant assimilation and offset photosynthetic gains. We measured growth parameters, photosynthesis, respiration, and biomass allocation of Pinus ponderosa seedlings grown for 2 months in 2×2 factorial treatments of 350 or 650μ bar CO2 and 10/25° C or 15/30° C night/day temperatures. After 1 month in treatment conditions, total seedling biomass was higher in elevated CO2, and temperature significantly enhanced the positive CO2 effect. However, after 2 months the effect of CO2 on total biomass decreased and relative growth rates did not differ among CO2 and temperature treatments over the 2-month growth period even though photosynthetic rates increased ≈7% in high CO2 treatments and decreased ≈10% in high temperature treatments. Additionally, CO2 enhancement decreased root respiration and high temperatures increased shoot respiration. Based on CO2 exchange rates, CO2 fertilization should have increased relative growth rates (RGR) and high temperatures should have decreased RGR. Higher photosynthetic rates caused by CO2 fertilization appear to have been mitigated during the second month of exposure to treatment conditions by a ≈3% decrease in allocation of biomass to leaves and a ≈9% increase in root:shoot ratio. It was not clear why diminished photosynthetic rates and increased respiration rates at high temperatures did not result in lower RGR. Significant diametrical and potentially compensatory responses of CO2 exchange and biomass allocation and the lack of differences in RGR of ponderosa pine after 2 months of exposure of high CO2 indicate that the effects of CO2 fertilization and temperature on whole-plant growth are determined by complex shifts in biomass allocation and gas exchange that may, for some species, maintain constant growth rates as climate and atmospheric CO2 concentrations change. These complex responses must be considered together to predict plant growth reactions to global atmospheric change, and the potential of forest ecosystems to sequester larger amounts of carbon in the future.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00341468
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 21
    Electronic Resource
    Electronic Resource
    Photosynthetic metabolism of cyanate by the cyanobacterium Synechococcus UTEX 625 (1994)
    Springer
    Archives of microbiology 162 (1994), S. 151-157 
    Details
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Synechococcus ; Cyanate metabolism ; Cyanase ; Photosynthesis ; CO2/HCO3 - transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Intact cells of the unicellular cyanobacterium Synechococcus UTEX 625 degraded exogenously supplied cyanate (as KOCN) to CO2 and NH3 in a light-dependent reaction. NH3 release to the medium was as high as 80 μmol(mgChl)-1h-1 and increased 1.7-fold in the presence of methionine sulfoximine, a glutamine synthetase inhibitor. Cyanate also supporte photosynthetic O2 evolution to a maximum rate of 188 μmol O2(mgChl)-1h-1 at pH 8 and 30°C. Cyanate decomposition in cell-free extracts, measured by mass spectrometry as 13CO2 production from KO13CN, occurred in the soluble enzyme fraction, but not in the thylakoid/carboxysome fraction, and was enhanced by HCO3 − and inhibited by the dianion oxalate. CO2, rather, than HCO3 −, was a product of cyanate decomposition. The ability to decompose cyanate was not dependent upon pre-exposure of cells to cyanate to induce activity. The collective results indicate that Synechococcus UTEX 625 possesses a constitutive, cytosolic cyanase (EC 4.3.99.1), similar in mechanism to that found in some species of heterotrophic bacteria. The reaction catalyzed was: OCN+HCO3+2H+→2CO2+NH3. In intact cells, the CO2 produced by the action of cyanase on OCN- was either directly fixed by the Calvin cycle enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase, leading to O2 evolution, or leaked into the medium where it was returned to the cell by the active CO2/HCO3 − transport systems for fixation. However, leakage of CO2 from air-grown cells was only observed when the active CO2 transport system was inhibited by darkness or the CO2 analogue carbon oxysulfide.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00314468
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    Photosynthetic metabolism of cyanate by the cyanobacterium Synechococcus UTEX 625 (1994)
    Springer
    Archives of microbiology 162 (1994), S. 151-157 
    Details
    ISSN: 1432-072X
    Keywords: Key words     Cyanobacteria ; Synechococcus ; Cyanate metabolism ; Cyanase ; Photosynthesis ; CO2/HCO3 ; transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract      Intact cells of the unicellular cyanobacterium Synechococcus UTEX 625 degraded exogenously supplied cyanate (as KOCN) to CO2 and NH3 in a light-dependent reaction. NH3 release to the medium was as high as 80 μmol(mgChl)–1h–1 and increased 1.7-fold in the presence of methionine sulfoximine, a glutamine synthetase inhibitor. Cyanate also supported photosynthetic O2 evolution to a maximum rate of 188 μmol O2(mgChl)–1h–1 at pH 8 and 30° C. Cyanate decomposition in cell-free extracts, measured by mass spectrometry as 13CO2 production from KO13CN, occurred in the soluble enzyme fraction, but not in the thylakoid/carboxysome fraction, and was enhanced by HCO3 – and inhibited by the dianion oxalate. CO2, rather than HCO3 –, was a product of cyanate decomposition. The ability to decompose cyanate was not dependent upon pre-exposure of cells to cyanate to induce activity. The collective results indicate that Synechococcus UTEX 625 possesses a constitutive, cytosolic cyanase (EC 4.3.99.1), similar in mechanism to that found in some species of heterotrophic bacteria. The reaction catalyzed was: OCN– + HCO3 – + 2 H+→ 2 CO2 + NH3. In intact cells, the CO2 produced by the action of cyanase on OCN– was either directly fixed by the Calvin cycle enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase, leading to O2 evolution, or leaked into the medium where it was returned to the cell by the active CO2/HCO3 – transport systems for fixation. However, leakage of CO2 from air-grown cells was only observed when the active CO2 transport system was inhibited by darkness or the CO2 analogue carbon oxysulfide.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00314468
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    Seasonal changes in the utilization and turnover of assimilation products in 8-year-old Scots pine (Pinus sylvestris L.) trees (1994)
    Springer
    Trees 8 (1994), S. 172-182 
    Details
    ISSN: 1432-2285
    Keywords: Pinus sylvestris ; Seasonal carbon metabolism ; Photosynthesis ; 14C labelling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The present study aimed at a physiological understanding of the seasonal changes of the carbohydrate patterns and levels in the various tissues of 8-year-old Scots pine (Pinus sylvestris L.) trees growing under ambient climatic conditions in the botanical garden at Bayreuth. The photosynthates of selected twig sections were labelled by 14CO2 fixation and after chase periods of 1 h up to 8 months, the distribution of radiocarbon in the whole trees was determined and the labelling of identified carbohydrates was compared with the levels of these compounds in the individual tissues. Bud break and sprouting in spring is exclusively supplied by the recent photosynthates of the previous year's needles. During summer assimilates of the old needles were utilized for secondary growth of the axial system while growth of the recent-year's shoots was supported by their own photosynthesis. In autumn, soluble carbohydrates were produced instead of starch, a major part of which in addition to recent photosynthates was utilized for root growth during the cold season. Another part of the autumnal storage material was incorporated into the cell walls of the latest xylem and phloem elements still in winter. A pronounced starch-oligosaccharide interconversion upon frost hardening, and its reversal in spring as has been described for deciduous trees, could not be observed. This was due to maintenance of photosynthetic capability even in the cold season and the replacement of consumed storage material especially in late winter and early spring by new photosynthates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00196844
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    Life expectancy of spruce needles under extremely high air pollution stress: performance of trees in the Ore Mountains (1994)
    Springer
    Trees 8 (1994), S. 213-222 
    Details
    ISSN: 1432-2285
    Keywords: Air pollution ; Forest decline ; Photosynthesis ; Picea abies ; Sulfur dioxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Photosynthetic performance of Norway spruce needles [Picea abies (L.) Karst.] was measured over a 1-year period. The trees grew in an area of heavy air pollution and forest decline on a mountain ridge in the eastern Ore Mountains (Czech Republic). Photosynthetic capacity, as well as light use efficiency, decreased dramatically with time, starting in July (2 months after bud-break) to finally reach zero (respiration only) by February of the following year. Two months later all needles from upper crown parts were shed. Needles from lower crown parts, on the other hand, were undamaged. The chlorophyll and Mg content decreased transiently during the cold season, with Mg reaching deficiency thresholds during winter. However, total sulfur, as well as organic and sulfate S increased with time. The increase was higher in needles from the upper parts of the crown, which were exposed to windy air throughout the year, than in the lower parts of the crown, which were covered by grass during summer and by snow during most of the winter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00196624
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 25
    Electronic Resource
    Electronic Resource
    Short-term effects of nitrate, nitrite and ammonium assimilation on photosynthesis, carbon partitioning and protein phosphorylation in maize (1994)
    Springer
    Planta 192 (1994), S. 211-220 
    Details
    ISSN: 1432-2048
    Keywords: Chlorophyll-a/b-binding protein complex ; Nitrogen assimilation ; Phosphoenolpyruvate carboxylase ; Photosynthesis ; Sucrose phosphate synthase ; Zea (photosynthesis)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Maize (Zea mays L. cv. Contessa) was grown with a nitrogen supply that was just sufficient to support maximal biomass production. The third leaves from 14-to 21-d-old plants were harvested and net photosynthesis allowed to attain steady-state rates at an irradiance of either 250 or 700 μmol·m−2·s−1. Nitrogen in the form of either KNO3, KNO2 or NH4Cl was then supplied to the leaves through the transpiration stream. In all cases the addition of the nitrogen source resulted in an approximate doubling of the total amino-acid content of the leaves within 1 h. The glutamine pool increased to ten times the level found in control leaves in the light in the absence of added nitrogen. Glutamine accounted for about 21–24% of the total amino-acid content in leaves fed with 40 mM NH4Cl. Nitrate caused a rapid, but transient inhibition of the rate of net CO2 assimilation, accompanied by an increase in the activity of phosphoenolpyruvate carboxylase and a decrease in the maximum extractable activity of sucrose-phosphate synthase. This demonstrates that the activities of phospho-enolpyruvate carboxylase and sucrose-phosphate synthase are modulated by NO 3 − in the C4 plant maize, in a similar manner to that observed in C3 plants. Nitrite or ammonium feeding resulted in decreased rates of CO2 assimilation for as long as the nitrogen source was supplied. In all cases the degree of inhibition was greatest at high irradiance and least at low irradiance, even though the total amino-acid contents of the leaves were comparable at the time when maximum inhibition of CO2 assimilation occurred. Measurements of chlorophyll-a fluorescence showed that the quantum efficiency of PSII decreased and non-radiative dissipation of excitation energy increased as CO2 assimilation was inhibited by nitrate or nitrite. These metabolites had no direct effect on thylakoid PSII-based electron transport. Ammonium ions weakly inhibited O2 evolution at high concentrations. The addition of nitrogen (KNO 3 − , KNO2 or NH4Cl) caused a significant decrease in the phosphorylation state of the light-harvesting chlorophyll-a/b-binding protein of the thylakoid membranes. We conclude that the response of photosynthetic carbon assimilation and electron transport in maize is essentially similar whether nitrogen is supplied in the form of nitrate, nitrite or ammonium, with the noteworthy exception that the nitrogen-induced inhibition of photosynthesis is transient when leaves are supplied with NO 3 − but sustained when NO 2 − or NH 4 + is provided. We suggest that the observed modulation of phosphoenolpyruvate carboxylase and sucrose-phosphate synthase is mediated by the increase in the endogenous level of glutamine. Furthermore, the transient nature of the inhibition of CO2 assimilation in the case of NO 3 − , but not NO 2 − or NH 4 + , may be due to regulation of nitrate reductase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01089037
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 26
    Electronic Resource
    Electronic Resource
    An improved method, using saturating light pulses, for the determination of photosystem I quantum yield via P700+-absorbance changes at 830 nm (1994)
    Springer
    Planta 192 (1994), S. 261-268 
    Details
    ISSN: 1432-2048
    Keywords: Chlorophyll fluorescence ; Light absorbance (830 nm) ; P700 ; Photosynthesis ; Quantum yield
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An improved method is introduced for the determination of the quantum yield of photosystem I. The new method employs saturating light pulses with steep rise characteristics to distinguish, in a given physiological state, centers with an open acceptor side from centers with a reduced acceptor side. The latter do not contribute to PSI quantum yield (ΦI). Oxidation of P700 is measured by a rapid modulation technique using the absorbance change around 830 nm. The quantum yield ΦI is calculated from the amplitude of the rapid phase of absorbance change (ΔA; 830 nm) upon application of a saturation pulse in a given state, divided by the maximal ΔA (830 nm) which is induced by a saturation pulse with far-red background illumination. Using this technique, ΦI can be determined even under conditions of acceptor-side limitation, as for example in the course of a dark-light induction period or after elimination of CO2 from the gas stream. Thus determined ΦI values display a close-to-linear relationship with those for the quantum yield of PSII (ΦII) calculated from chlorophyll fluorescence parameters. It is concluded that the proposed method may provide new information on the activity of the PSI acceptor side and thus help to separate the effects of acceptorside limitation from those of cyclic PSI, whenever a non-linear relationship between ΦII and the P700-reduction level is observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01089043
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 27
    Electronic Resource
    Electronic Resource
    The site of photoinhibition in leaves of Cucumis sativus L. at low temperatures is photosystem I, not photosystem II (1994)
    Springer
    Planta 193 (1994), S. 300-306 
    Details
    ISSN: 1432-2048
    Keywords: Chilling stress ; Cucumis (Cucurbitaceae, cucumber) ; Photosynthesis ; Thylakoid ; Photoinhibition ; Photosystem I
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Maximum quantum yields (QY) of photosynthetic electron flows through PSI and PSII were separately assessed in thylakoid membranes isolated from leaves of Cucumis sativus L. (cucumber) that had been chilled in various ways. The QY(PSI) in the thylakoids prepared from the leaves treated at 4° C in moderate light at 220 μmol quanta·m−2·s−1 (400–700 nm) for 5 h, was about 20–30% of that in the thylakoids prepared from untreated leaves, while QY(PSII) decreased, at most, by 20% in response to the same treatment. The decrease in QY(PSI) was observed only when the leaves were chilled at temperatures below 10° C, while such a marked temperature dependency was not observed for the decrease in QY(PSII). In the chilling treatment at 4° C for 5 h, the quantum flux density that was required to induce 50% loss of QY (PSI) was ca. 50 umol quanta·m−2·s−1. When the chilling treatment at 4° C in the light was conducted in an atmosphere of N2, photoinhibition of PSI was largely suppressed, while the damage to PSII was somewhat enhanced. The ferricyanide-oxidised minus ascorbate-reduced difference spectra and the light-induced absorbance changes at 700 nm obtained with the thylakoid suspension, indicated the loss of P700 to extents that corresponded to the decreases in QY(PSI). Accordingly, the decreases in QY(PSI) can largely be attributed to destruction of the PSI reaction centre itself. These results clearly show that, at least in cucumber, a typical chillingsensitive plant, PSI is much more susceptible to aerobic photoinhibition than PSII.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00192544
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 28
    Electronic Resource
    Electronic Resource
    Cloning, structure and expression of a pea cDNA clone coding for a photosynthetic fructose-1,6-bisphosphatase with some features different from those of the leaf chloroplast enzyme (1994)
    Springer
    Planta 193 (1994), S. 494-501 
    Details
    ISSN: 1432-2048
    Keywords: Calvin cycle ; Chloroplast ; Fructose-1,6-bisphosphatase ; Photosynthesis ; Pisum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A positive clone against pea (Pisum sativum L.) chloroplast fructose-1,6-bisphosphatase (FBPase; EC 3.1.3.11) antibodies was obtained from a copy DNA (cDNA) library in λgt11. The insert was 1261 nucleotides long, and had an open reading frame of 1143 base pairs with coding capability for the whole FBPase subunit and a fragment of a putative processing peptide. An additional 115 base pairs corresponding to a 3′-untranslated region coding for an mRNA poly(A)+ tail were also found in the clone. The deduced sequence for the FBPase subunit was a 357-amino-acid protein of molecular mass 39253 daltons (Da), showing 82–88% absolute homology with four chloroplastic FBPases sequenced earlier. The 3.1-kilobase (kb)KpnI-SacI fragment of the λgt11 derivative was subcloned between theKpnI-SacI restriction sites of pTZ18R to yield plasmid pAMC100. Lysates ofEscherichia coli (pAMC100) showed FBPase activity; this was purified as a 170-kDa protein which, upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis, displayed a 44-kDa band. As occurs with native FBPases, this indicates a homotetrameric structure for the expressed FBPase. When assayed under excess Mg2+ (10 mM), the expressed enzyme had a higher affinity for the substrate than the native pea leaf FBPase; this parameter appears to be substantiated by a tenfold higher specific activity than that of the native enzyme. However, when activated with dithiothreitol plus saturating concentrations of pea thioredoxin (Td) f, both FBPase had similar activities, with a 4:1 Td f-FBPase stoichiometry. In contrast to the native pea chloroplast FBPase, theE. coli-expressed enzyme did not react with the monoclonal antibody GR-PB5. It also had a higher heat sensitivity, with 42% residual activity after heating for 30 min at 60°C, conditions which preserved the native enzyme in a fully active state. These results show the existence of some difference(s) in the conformation of the two FBPases; this could be a consequence of a different expression of the genomic and cDNA clones, or be due to the need for some factor for the correct assembly of the oligomeric structure of the native chloroplast enzyme.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02411553
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 29
    Electronic Resource
    Electronic Resource
    Accumulation of hexoses in leaf vacuoles: Studies with transgenic tobacco plants expressing yeast-derived invertase in the cytosol, vacuole or apoplasm (1994)
    Springer
    Planta 194 (1994), S. 29-33 
    Details
    ISSN: 1432-2048
    Keywords: Amino acid ; Hexose uptake ; Nicotiana ; Photosynthesis ; Sucrose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The subcellular distribution of hexoses, sucrose and amino acids among the stromal, cytosolic and vacuolar compartments was analysed by a nonaqueous fractionation technique in leaves of tobacco (Nicotiana tabaccum L.) wild-type and transgenic plants expressing a yeast-derived invertase in the cytosolic, vacuolar or apoplasmic compartment. In the wild-type plants the amino acids were found to be located in the stroma and in the cytosol, sucrose mainly in the cytosol and up to 98% of the hexoses in the vacuole. In the leaves of the various transformants, where the contents of hexoses were greater than in wild-type plants, again 97–98% of these hexoses were found in the vacuoles. It is concluded that leaf vacuoles contain transporters for the active uptake of glucose and fructose against a high concentration gradient. A comparison of estimated metabolite concentrations in the subcellular compartments of wild-type and transformant plants indicated that the decreased photosynthetic capacity of the transformants is not due to an osmotic effect on photosynthesis, as was shown earlier to be the case in transformed potato leaves, but is the result of a long-term dedifferentiation of tobacco leaf cells to heterotrophic cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00201031
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 30
    Electronic Resource
    Electronic Resource
    Effect of inorganic carbon supply on the photosynthetic physiology of Gracilaria tenuistipitata (1994)
    Springer
    Planta 194 (1994), S. 55-61 
    Details
    ISSN: 1432-2048
    Keywords: Carbonic anhydrase ; Chlorophyll ; Gracilaria ; Inorganic carbon ; Ribulose-1,5-bisphosphate carboxylase/oxygenase ; Phycobiliprotein ; Photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Gracilaria tenuistipitata Zhang et Xia was cultured for 15 d at low, normal and high inorganic carbon concentrations under constant light, temperature and nutrient conditons. Carbonic anhydrase (CA; EC 4.2.1.1.) activity, ribulose-1,5-bisphosphate carboxylase/ oxygenase (Rubisco; EC 4.1.1.39) content, pigment content and C/N ratio were measured, and also the photosynthesis and growth rates. Both Rubisco content and CA activity increased under conditions of low inorganic carbon (Ci) but decreased at high Ci with respect to the control. The amount of pigments declined considerably at high Ci and was slightly higher at low Ci. The maximum rate of photosynthesis and the photosynthetic efficiency increased in low Ci and the opposite was found at high Ci concentration. The effects of Ci concentration on maximum rate of photosynthesis and photosynthetic efficiency are discussed in relation to the variation in pigment and Rubisco contents and CA activity. The data indicate that Ci may be an important factor controlling the photosynthetic physiology of G. tenuistipitata with regard, not only to the enzymes of Ci metabolism, but also to the pigment content.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00201034
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 31
    Electronic Resource
    Electronic Resource
    Mechanism of photosystem-I photoinhibition in leaves ofCucumis sativus L. (1994)
    Springer
    Planta 194 (1994), S. 287-293 
    Details
    ISSN: 1432-2048
    Keywords: Chilling stress ; Cucumis (photoinhibition) ; Photoinhibition ; Photosynthesis ; Photosystem I ; Subunit protein degradation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract It was recently shown that the site of photoinhibition in leaves ofCucumis sativus L. at low temperatures is Photosystem I (PSI), not PSII (I. Terashima et al. 1994, Planta193, 300–306). In the present study, the mechanisms of this PSI photoinhibition in vivo were examined. By lowering the photon flux density during the photoinhibitory treatment of leaves at 4°C for 5 h to less than 100 μmol·m−2s−1, we were able to separate the steps of the destruction of the electron-transfer components. Although P-700, the reaction-center chlorophyll, was almost intact in this low-light treatment, the quantum yield of the electron transfer through PSI and photochemically induced absorption change at 701 nm were markedly inhibited. This, along with the results from the measurements of the light-induced absorption changes in the presence of various concentrations of methyl viologen, an artificial electron acceptor, indicates that the component on the acceptor side of the PSI, A1 or Fx, is the first site of inactivation. When the photon flux density during the treatment was increased to 220 μmol·m−2s−1, the destruction of P-700 itself was also observed. Furthermore, the partial degradation of the chlorophyll-binding large subunits was observed in photoinhibited leaves. This degradation of the subunits was not detected when the treatment was carried out under nitrogen atmosphere, the condition in which the electron transfer is not inhibited. Thus, the photoinhibitory processes in the reaction center of PSI go through three steps, the inactivation of the acceptor side, the destruction of the reaction-center chlorophyll and the degradation of the reaction center subunit(s). The similarities and the differences between the mechanisms of PSI photoinhibition and those of PSII photoinhibition are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01101690
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 32
    Electronic Resource
    Electronic Resource
    Acclimation of Arabidopsis thaliana to the light environment: Changes in composition of the photosynthetic apparatus (1994)
    Springer
    Planta 195 (1994), S. 248-256 
    Details
    ISSN: 1432-2048
    Keywords: Arabidopsis ; Chlorophyll-binding proteins ; Photomorphogenesis ; Photosynthesis ; Photosystem stoichiometry ; Thylakoid membrane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Acclimation to changes in the light environment was investigated in Arabidopsis thaliana (L.) Heynh. cv. Landsberg erecta. Plants grown under four light regimes showed differences in their development, morphology, photosynthetic performance and in the composition of the photosynthetic apparatus. Plants grown under high light showed higher maximum rates of oxygen evolution and lower levels of light-harvesting complexes than their low light-grown counterparts; plants transferred to low light showed rapid changes in maximum photosynthetic rate and chlorophyll-a/b ratio as they became acclimated to the new environment. In contrast, plants grown under lights of differing spectral quality showed significant differences in the ratio of photosystem II to photosystem I. These changes are consistent with a model in which photosynthetic metabolism provides signals which regulate the composition of the thylakoid membrane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00199685
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 33
    Electronic Resource
    Electronic Resource
    Xanthophyll cycle and energy-dependent fluorescence quenching in leaves from pea plants grown under intermittent light (1994)
    Springer
    Planta 192 (1994), S. 176-182 
    Details
    ISSN: 1432-2048
    Keywords: Chlorophyll a/b-binding protein ; Energy-dependent fluorescence quenching ; Intermittent light ; Photosynthesis ; Pisum ; Xanthophyll cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The possible role of zeaxanthin formation and antenna proteins in energy-dependent chlorophyll fluorescence quenching (qE) has been investigated. Intermittent-light-grown pea (Pisum sativum L.) plants that lack most of the chlorophyll a/b antenna proteins exhibited a significantly reduced qE upon illumination with respect to control plants. On the other hand, the violaxanthin content related to the number of reaction centers and to xanthophyll cycle activity, i.e. the conversion of violaxanthin into zeaxanthin, was found to be increased in the antenna-protein-depleted plants. Western blot analyses indicated that, with the exception of CP 26, the content of all chlorophyll a/b-binding proteins in these plants is reduced to less than 10% of control values. The results indicate that chlorophyll a/b-binding antenna proteins are involved in the energy-dependent fluorescence quenching but that only a part of qE can be attributed to quenching by chlorophyll a/b-binding proteins. It seems very unlikely that xanthophylls are exclusively responsible for the qE mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00194450
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 34
    Electronic Resource
    Electronic Resource
    Short-term effects of nitrate, nitrite and ammonium assimilation on photosynthesis, carbon partitioning and protein phosphorylation in maize (1994)
    Springer
    Planta 192 (1994), S. 211-220 
    Details
    ISSN: 1432-2048
    Keywords: Chlorophyll-a/b-binding protein complex ; Nitrogen assimilation ; Phosphoenolpyruvate carboxylase ; Photosynthesis ; Sucrose phosphate synthase ; Zea (photosynthesis)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Maize (Zea mays L. cv. Contessa) was grown with a nitrogen supply that was just sufficient to support maximal biomass production. The third leaves from 14-to 21-d-old plants were harvested and net photosynthesis allowed to attain steady-state rates at an irradiance of either 250 or 700 μmol·m−2·s−1. Nitrogen in the form of either KNO3, KNO2 or NH4Cl was then supplied to the leaves through the transpiration stream. In all cases the addition of the nitrogen source resulted in an approximate doubling of the total amino-acid content of the leaves within 1 h. The glutamine pool increased to ten times the level found in control leaves in the light in the absence of added nitrogen. Glutamine accounted for about 21–24% of the total amino-acid content in leaves fed with 40 mM NH4Cl. Nitrate caused a rapid, but transient inhibition of the rate of net CO2 assimilation, accompanied by an increase in the activity of phosphoenolpyruvate carboxylase and a decrease in the maximum extractable activity of sucrose-phosphate synthase. This demonstrates that the activities of phospho-enolpyruvate carboxylase and sucrose-phosphate synthase are modulated by NO 3 − in the C4 plant maize, in a similar manner to that observed in C3 plants. Nitrite or ammonium feeding resulted in decreased rates of CO2 assimilation for as long as the nitrogen source was supplied. In all cases the degree of inhibition was greatest at high irradiance and least at low irradiance, even though the total amino-acid contents of the leaves were comparable at the time when maximum inhibition of CO2 assimilation occurred. Measurements of chlorophyll-a fluorescence showed that the quantum efficiency of PSII decreased and non-radiative dissipation of excitation energy increased as CO2 assimilation was inhibited by nitrate or nitrite. These metabolites had no direct effect on thylakoid PSII-based electron transport. Ammonium ions weakly inhibited O2 evolution at high concentrations. The addition of nitrogen (KNO 3 − , KNO2 or NH4Cl) caused a significant decrease in the phosphorylation state of the light-harvesting chlorophyll-a/b-binding protein of the thylakoid membranes. We conclude that the response of photosynthetic carbon assimilation and electron transport in maize is essentially similar whether nitrogen is supplied in the form of nitrate, nitrite or ammonium, with the noteworthy exception that the nitrogen-induced inhibition of photosynthesis is transient when leaves are supplied with NO 3 − but sustained when NO 2 − or NH 4 + is provided. We suggest that the observed modulation of phosphoenolpyruvate carboxylase and sucrose-phosphate synthase is mediated by the increase in the endogenous level of glutamine. Furthermore, the transient nature of the inhibition of CO2 assimilation in the case of NO 3 − , but not NO 2 − or NH 4 + , may be due to regulation of nitrate reductase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00194455
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 35
    Electronic Resource
    Electronic Resource
    An improved method, using saturating light pulses, for the determination of photosystem I quantum yield via P700+-absorbance changes at 830 nm (1994)
    Springer
    Planta 192 (1994), S. 261-268 
    Details
    ISSN: 1432-2048
    Keywords: Chlorophyll fluorescence ; Light absorbance (830 nm) ; P700 ; Photosynthesis ; Quantum yield
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An improved method is introduced for the determination of the quantum yield of photosystem I. The new method employs saturating light pulses with steep rise characteristics to distinguish, in a given physiological state, centers with an open acceptor side from centers with a reduced acceptor side. The latter do not contribute to PSI quantum yield (ΦI). Oxidation of P700 is measured by a rapid modulation technique using the absorbance change around 830 nm. The quantum yield ΦI is calculated from the amplitude of the rapid phase of absorbance change (ΔA; 830 nm) upon application of a saturation pulse in a given state, divided by the maximal ΔA (830 nm) which is induced by a saturation pulse with far-red background illumination. Using this technique, ΦI can be determined even under conditions of acceptor-side limitation, as for example in the course of a dark-light induction period or after elimination of CO2 from the gas stream. Thus determined ΦI values display a close-to-linear relationship with those for the quantum yield of PSII (ΦII) calculated from chlorophyll fluorescence parameters. It is concluded that the proposed method may provide new information on the activity of the PSI acceptor side and thus help to separate the effects of acceptorside limitation from those of cyclic PSI, whenever a non-linear relationship between ΦII and the P700-reduction level is observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00194461
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 36
    Electronic Resource
    Electronic Resource
    Xanthophyll cycle and energy-dependent fluorescence quenching in leaves from pea plants grown under intermittent light (1994)
    Springer
    Planta 192 (1994), S. 176-182 
    Details
    ISSN: 1432-2048
    Keywords: Chlorophyll a/b-binding protein ; Energy-dependent fluorescence quenching ; Intermittent light ; Photosynthesis ; Pisum ; Xanthophyll cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The possible role of zeaxanthin formation and antenna proteins in energy-dependent chlorophyll fluorescence quenching (qE) has been investigated. Intermittent-light-grown pea (Pisum sativum L.) plants that lack most of the chlorophyll a/b antenna proteins exhibited a significantly reduced qE upon illumination with respect to control plants. On the other hand, the violaxanthin content related to the number of reaction centers and to xanthophyll cycle activity, i.e. the conversion of violaxanthin into zeaxanthin, was found to be increased in the antenna-protein-depleted plants. Western blot analyses indicated that, with the exception of CP 26, the content of all chlorophyll a/b-binding proteins in these plants is reduced to less than 10% of control values. The results indicate that chlorophyll a/b-binding antenna proteins are involved in the energy-dependent fluorescence quenching but that only a part of qE can be attributed to quenching by chlorophyll a/b-binding proteins. It seems very unlikely that xanthophylls are exclusively responsible for the qE mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01089032
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 37
    Electronic Resource
    Electronic Resource
    Reconstitution of chlorophylls and photosynthetic CO2 assimilation upon rehydration of the desiccated poikilochlorophyllous plant Xerophyta scabrida (Pax) Th. Dur. et Schinz (1994)
    Springer
    Planta 192 (1994), S. 414-420 
    Details
    ISSN: 1432-2048
    Keywords: Carotenoid ; Chlorophyll fluorescence ; Photosynthesis ; Rehydration respiration ; Variable-fluorescence decrease ratio ; Xerophyta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Resynthesis of the photosynthetic apparatus and resumption of CO2 assimilation upon rehydration is reported for the monocotyledonous and poikilochlorophyllous desiccation-tolerant (PDT) plant Xerophyta scabrida (Pax) Th. Dur. et Schinz (Velloziaceae). During desiccation there was a complete breakdown of chlorophylls whereas the total carotenoid content of air-dried leaves was reduced to about 22% of that of functional leaves. The prerequisites for the resynthesis of photosynthetic pigments and functional thylakoids were the reappearance of turgor and maximum leaf water content at 2 and 10 h after rehydration, respectively. The period of increased initial respiration after rewetting leaves (rehydration respiration) lasted up to 30 h and was thus 6 to 10 times longer than in homoiochlorophyllous desiccation-tolerant plants (HDTs) in which chlorophylls are retained during desiccation. Accumulation of chlorophylls a + b and total carotenoids (xanthophylls and βcarotene) started 10 h after rehydration. Normal levels of chlorophyll and carotenoids were obtained 72 h after rehydration. Values for the variable-fluorescence decrease ratio (Rfd690 values), an indicator of photochemical activity, showed that photochemical function started 10 h after rehydration, but normal values of 2.7 were reached only 72 h after rehydration. Net CO2 assimilation started 24 h after rewetting and normal rates were reached after 72 h, at the same time as normal values of stomatal conductance were obtained. The increasing rates of net CO2 assimilation were paralleled by decreasing values of the intercellular CO2 concentration. All photosynthetic parameters investigated showed values normal for functional chloroplasts by 72 h after the onset of rehydration. Fully regreened leaves of the presumed C3 plant X. scabrida exhibited a net CO2 assimilation rate which was in the same range as that of other C3 plants and higher than that of recovered HDT plants. The fundamental difference between air-dried PDT plants, such as X. scabrida, which have to resynthesize the photosynthetic pigment apparatus, and air-dried HDT plants, which only undergo a functional recovery, is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00198578
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 38
    Electronic Resource
    Electronic Resource
    Adenine nucleotides and the xanthophyll cycle in leaves (1994)
    Springer
    Planta 192 (1994), S. 537-544 
    Details
    ISSN: 1432-2048
    Keywords: Adenylate energy charge ; ATPase activity ; Energy dissipation ; Gossypium ; Photosynthesis ; Stress (low temperature, low CO2) ; xanthophyll cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The relationships among the leaf adenylate energy charge, the xanthophyll-cycle components, and photosystem II (PSII) fluorescence quenching were determined in leaves of cotton (Gossypium hirsutum L. cv. Acala) under different leaf temperatures and different intercellular CO2 concentrations (Ci). Attenuating the rate of photosynthesis by lowering the Ci at a given temperature and photon flux density increased the concentration of high-energy adenylate phosphate bonds (adenylate energy charge) in the cell by restricting ATP consumption (A.M. Gilmore, O. Björkman 1994, Planta 192, 526–536). In this study we show that decreases in photosynthesis and increases in the adenylate energy charge at steady state were both correlated with decreases in PSII photo-chemical efficiency as determined by chlorophyll fluorescence analysis. Attenuating photosynthesis by decreasing Ci also stimulated violaxanthin-de-epoxidation-dependent nonradiative dissipation (NRD) of excess energy in PSII, measured by nonphotochemical fluorescence quenching. However, high NRD levels, which indicate a large trans-thylakoid proton gradient, were not dependent on a high adenylate energy charge, especially at low temperatures. Moreover, dithiothreitol at concentrations sufficient to fully inhibit violaxanthin de-epoxidation and strongly inhibit NRD, affected neither the increased adenylate energy charge nor the decreased PSII photo-chemical efficiency that result from inhibiting photosynthesis. The build-up of a high adenylate energy charge in the light that took place at low Ci and low temperatures was accompanied by a slowing of the relaxation of non-photochemical fluorescence quenching after darkening. This slowly relaxing component of nonphotochemical quenching was also correlated with a sustained high adenylate energy charge in the dark. These results indicate that hydrolysis of ATP that accumulated in the light may acidify the lumen and thus sustain the level of NRD for extended periods after darkening the leaf. Hence, sustained nonphotochemical quenching often observed in leaves subjected to stress, rather than being indicative of photoinhibitory damage, apparently reflects the continued operation of NRD, a photoprotective process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00203592
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 39
    Electronic Resource
    Electronic Resource
    Light-stimulated proton transport into the vacuoles of leaf mesophyll cells does not require energization by the tonoplast pyrophosphatase (1994)
    Springer
    Planta 193 (1994), S. 203-207 
    Details
    ISSN: 1432-2048
    Keywords: Nicotiana ; Photosynthesis ; Proton pumping ; Pyrophosphatase ; Transgenic tobacco ; Vacuole
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Photosynthetic characteristics of transgenic tobacco (Nicotiana tabacum L.) plants with a soluble pyrophosphatase in the cytosol of their leaf cells were compared to those of wild-type plants. Although the development of the transgenic plants was somewhat retarded compared to the wild type, as shown by stunted growth and delayed flowering, photosynthetic responses were comparable in transgenic and wild-type leaves of similar physiological age. In particular, light-dependent proton transport into the vacuoles of leaf mesophyll cells was not decreased in leaves of the transgenic plants, which did not contain pyrophosphate in the cytosol owing to the presence of a soluble pyrophosphase. This shows that light-stimulated proton pumping did not require the pumping activity of the tonoplast pyrophosphatase. Apparently, light-stimulated proton pumping can be based solely on the activity of the tonoplast ATPase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00192531
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 40
    Electronic Resource
    Electronic Resource
    Photosynthetic electron transport is differentially affected during early stages of cultivar/race-specific interactions between potato andPhytophthora infestans (1994)
    Springer
    Planta 193 (1994), S. 551-557 
    Details
    ISSN: 1432-2048
    Keywords: Chlorophylla fluorescence ; Cultivar/race specific interactions (physiological marker) ; Photosynthesis ; Phytophthora ; Solanum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The influence of the early stages of fungal infection on chloroplast metabolism was studied in cultivar/race-specific interactions between potato (Solanum tuberosum L. cv. Datura) and the late-blight fungusPhytophthora infestans. The accumulation of several mRNAs encoding components of the photosynthetic apparatus was not affected, either in compatible or in incompatible interactions. However, within 3 h after inoculation of potato leaves with fungal spores, a change in the photochemistry of photosystem II was detectable by measuring chlorophylla fluorescence. Characteristic fluorescence parameters, such as maximum fluorescence yield (Fm), variable fluorescence yield (Fv) and photochemical efficiency (Fv/Fm), were specifically reduced in the compatible host/pathogen interaction. Analyses of photochemical and nonphotochemical fluorescence quenching showed an increase in the photochemical fraction. The amounts of two selected thylakoid membrane proteins and of total chlorophyll remained unchanged during this process, suggesting that the functional modification of the electron-transport system was not correlated with a change in the composition of the photosynthetic apparatus. The alterations of photosynthetic electron transport represent a rapidly detectable and sensitive physiological marker for compatible interactions in the potato/Phytophthora infestans pathosystem.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02411561
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 41
    Electronic Resource
    Electronic Resource
    Activation of non-photochemical quenching in thylakoids and leaves (1994)
    Springer
    Planta 194 (1994), S. 550-556 
    Details
    ISSN: 1432-2048
    Keywords: Chlorophyll fluorescence ; Chenopodium Digitalis ; Non-photochemical quenching ; Photosynthesis ; Xanthophyll cycle ; Zeaxanthin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The mechanism of rapidly-relaxing non-photochemical quenching in two plant species,Chenopodium album L. andDigitalis purpurea L., that differ considerably in their capacity for such quenching has been investigated (Johnson G.N. et al. 1993, Plant Cell Environ.16, 673–679). Illumination of leaves of both species in the presence of 2% O2 balance N2 led to the formation of zeaxanthin. When thylakoids were isolated from leaves of each species that had been so treated it was found that inD. purpurea non-photochemical quenching was “activated” relative to the control; a higher level of quenching was found for a given trans-thylakoid pH gradient. No such activation of non-photochemical quenching was observed inC. album. Similar conclusions were drawn when comparing quenching in intact leaves. It is concluded that light activation of quenching is a process that cannot readily be induced inC. album. Measurement of the sensitivity of non-photochemical quenching in leaves ofC. album andD. purpurea to dithiothreitol (DTT; a reagent that inhibits formation of zeaxanthin) showed differences between the two species. In both cases, feeding leaves with DTT inhibited the light-induced formation of zeaxanthin. InC. album this was accompanied by complete inhibition of reversible non-photochemical quenching, whereas inD. purpurea this inhibition was only partial. Data are discussed in relation to studies on the mechanism of quenching and the role of zeaxanthin in this process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00714469
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 42
    Electronic Resource
    Electronic Resource
    Seasonal fluctuations of photosynthesis and its pigments in 1-year mycorrhized spruce seedlings (1994)
    Springer
    Mycorrhiza 4 (1994), S. 277-281 
    Details
    ISSN: 1432-1890
    Keywords: Ectomycorrhiza ; Inoculation ; Photosynthesis ; Photosynthetic pigments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Specimens of spruce Picea abies (L.) Karsten were inoculated with the fungi Laccaria laccata, Pisolithus tinctorius and Lactarius piperatus in a nursery at the time of sowing. The 1-year seedlings were then tested in two growth periods for their photosynthesis, chlorophyll and carotenoid levels, and water potential; their roots were examined with a scanning electron microscope. Increased photosynthetic activity was determined at the start of the growth season in only those seedlings inoculated with the fungus Laccaria laccata. The levels of chlorophyll and carotenoids measured in September in the needles of all three mycorrhized groups of plants were higher than in the controls.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00206777
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 43
    Electronic Resource
    Electronic Resource
    Solar-tracking leaf movements in velvetleaf (Abutilon theophrasti) (1994)
    Springer
    Plant ecology 112 (1994), S. 93-99 
    Details
    ISSN: 1573-5052
    Keywords: Competition ; Diaheliotropism ; Photosynthesis ; Transpiration ; Water use efficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Leaves of velvetleaf (Abutilon theophrasti) exhibited solar-tracking movements in several experiments using different cultural conditions near Ames, IA, U.S.A. Freely moving leaves maintained a smaller angle between the normal to the leaf and the sun's rays than did leaves fixed in one position in both greenhouse and field experiments. Freely moving leaves had higher total daily carbon gain, transpiration, and water use efficiency than leaves fixed in a horizontal position. Leaves on different sides of the plant exhibited different abilities to track the sun, with leaves on the north side of the plant least able to track the sun.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00044684
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 44
    Electronic Resource
    Electronic Resource
    Filamentous algae in fish ponds of the Třeboň Biosphere Reserve-ecophysiological study (1994)
    Springer
    Plant ecology 113 (1994), S. 155-170 
    Details
    ISSN: 1573-5052
    Keywords: Biomass ; Cladophora fracta ; Decomposition ; Nutrient content ; Photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Filamentous algae in eutrophic carp ponds in South Bohemia (Central Europe) were studied from 1988 to 1990. High biomass (490 g DW m-2) was attained by Cladophora fracta (O. F. Müll. ex Vahl) Kütz. after two months of growth. This marked growth depleted inorganic carbon in the water, but did not decrease the concentration of tissue nutrients. Laboratory measurements of final pH indicate that all the filamentous algae studied, except for Tribonema, are very efficient HCO3 - users. An extremely high pH of 11.6 and oxygen concentration of 32 mg l-1 were measured in the algal mats. High pH resulted in CaCO3 precipitation, visible as white incrustations on algal filaments. The amount of precipitated CaCO3 reached 134 kg ha-1. After reaching peak biomass, 90% of the Cladophora decomposed over the next 95 days. The highest net photosynthetic rate in C. fracta was measured between pH range 8.5–10.0 and oxygen concentrations of 7–12 mg l-1. Optimum temperature for photosynthesis was between 17–22°C.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00044232
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 45
    Electronic Resource
    Electronic Resource
    Biochemistry of C3-photosynthesis in high CO2 (1994)
    Springer
    Journal of plant research 107 (1994), S. 79-84 
    Details
    ISSN: 1618-0860
    Keywords: C3 plants ; Electron transport ; High CO2 ; Photosynthesis ; Pi regeneration ; Rubisco
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The short-term responses of C3 photosynthesis to high CO2 are described first. Regulation of photosynthesis in the short term is determined by interaction among the capacities of light harvesting, electron transport, ribulose-1, 5-bisphosphate carboxylase (Rubisco) and orthophosphate (Pi) regeneration during starch and sucrose synthesis. Photosynthesis under high CO2 conditions is limited by either electron transport or Pi regeneration capacities, and Rubisco is deactivated to maintain a balance between each step in the photosynthetic pathway. Subsequently, the long-term effects on, photosynthesis are discussed. Long-term CO2 enhancement leads to carbohydrate accumulation. Accumulation of carbohydrates is not associated with a Pi-regeneration limitation on photosynthesis, and this limitation is apparently removed during long-term exposure to high CO2. Enhanced CO2 does not affect Rubisco content and electron transport capacity for a given leaf-nitrogen content. In addition, the deactivated Rubisco immediately after exposure to high CO2 does not recover during the subsequent prolonged exposure. Such evidence may indicate that plants do not necessarily have an ideal acclimation response to high CO2 at the biochemical level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02344533
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 46
    Electronic Resource
    Electronic Resource
    Comparative and evolutionary aspects of the photosynthetic electron transfer system of purple bacteria (1994)
    Springer
    Journal of plant research 107 (1994), S. 191-200 
    Details
    ISSN: 1618-0860
    Keywords: Photosynthesis ; Electron transfer ; Purple bacteria ; Reaction center ; Cytochromec ; Cytochromebc complex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The cyclic electron transfer system in purple bacteria is composed of the photosynthetic reaction center, the cytochromebc 1 complex, cytochromec 2, and ubiquinone. These components share many characteristics with those of photosynthesis and respiration in other organisms. Studies of the cyclic electron transfer system have provided useful insights about the evolution and general mechanisms of membranous energy-conserving systems. The photosynthetic system in purple bacteria may represent a prototype of highly efficient, energy-conserving electron transfer systems in the organisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02346017
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 47
    Electronic Resource
    Electronic Resource
    Effects of sulfur dioxide and ozone on intact leaves and isolated mesophyll cells of groundnut plants (Arachis hypogaea L.) (1994)
    Springer
    Journal of plant research 107 (1994), S. 229-235 
    Details
    ISSN: 1618-0860
    Keywords: Air pollutant ; Cell viability ; Photosynthesis ; Stomata ; Visible injury
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Difference between effects of sulfur dioxide (SO2) and ozone (O3) on groundnut plants (Arachis hypogaea L.) was studied by use of an exposure system of enzymatically-isolated mesophyll cells. SO2 inhibited photosynthesis of intact groundnut leaves but induced no visible injury on leaves. SO2 also inhibited photosynthesis of isolated mesophyll cells but did not kill the cells, suggesting that SO2 inhibits photosynthesis by attacking rather specifically the photosynthetic apparatus in chloroplasts. O3 inhibited photosynthesis of intact leaves and at the same time induced visible injury corresponding to the extent of photosynthesis inhibition. O3 also inhibited photosynthesis of isolated mesophyll cells and killed the cells to the extent corresponding to photosynthesis inhibition, suggesting that O3 inhibits photosynthesis not directly by attacking the photosynthetic apparatus but indirectly by killing cells. Since the response of intact leaves to each pollutant resembled that of isolated mesophyll cells, the difference between responses of intact leaves to both pollutants may considerably reflect that of mesophyll cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02344249
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 48
    Electronic Resource
    Electronic Resource
    Effect of fruiting on carbon budgets of apple tree canopies (1993)
    Springer
    Trees 8 (1993), S. 56-60 
    Details
    ISSN: 1432-2285
    Keywords: Malus domestica ; Bioenergetics ; Fruit ; Photosynthesis ; Respiration ; Source-sink
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Carbon budgets were calculated from net photosynthesis and dark respiration measurements for canopies of field-grown, 3-year-old apple trees (Malus domestica Borkh.) with maximum leaf areas of 5.4 m2 in a temperature-controlled Perspex tree chamber, measured in situ over 2 years (July 1988 to October 1990) by computerized infrared gas analysis using a dedicated interface and software. Net photosynthesis (Pn) and carbon assimilation per leaf area peaked at respectively 8.3 and 7.7 μmol CO2 m−2 s−1 in April. Net photosynthesis (Pn) and dark respiration (Rd) per tree peaked at 3.6 g CO2 tree−1 h−1 (Pn) and 1.2 g CO2 tree−1 h−1 (Rd), equivalent to 4.2 μmol CO2 (Pn) and 1.4 μmol CO2 (Rd) m−2 s−1 with maximum carbon gain per tree in August and maximum dark respiration per tree in October 1988 and 1989. In May 1990, a tree was deblossomed. Pn (per tree) of the fruiting apple tree canopy exceeded that of the non-fruiting tree by 2–2.5 fold from June to August 1990, attributed to reduced photorespiration (RI), and resulting in a 2-fold carbon gain of the fruiting over the non-fruiting tree. Dark respiration of the fruiting tree canopy progressively exceeded, with increasing sink strength of the fruit, by 51% (June–August), 1.4-fold (September) and 2-fold (October) that of the non-fruiting tree due to leaf (i. e. not fruit) respiration to provide energy (a) to produce and maintain the fruit on the tree and (b) thereafter to facilitate the later carbohydrate translocation into the woody perennial parts of the tree. The fruiting tree reached its optium carbon budget 2–4 weeks earlier (August) then the non-fruiting tree (September 1990). In the winter, the trunk respired 2–100 g CO2 month−1 tree−1. These data represent the first long-term examination of the effect of fruiting without fruit removal which shows increased dark respiration and with the increase progressing as the fruit developed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00240982
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 49
    Electronic Resource
    Electronic Resource
    Decreased ribulose-1,5-bisphosphate carboxylase-oxygenase in transgenic tobacco transformed with “antisense” rbcS (1993)
    Springer
    Planta 190 (1993), S. 1-9 
    Details
    ISSN: 1432-2048
    Keywords: Biomass allocation ; Nicotiana ; Nitrogen nutrition ; Photosynthesis ; Relative growth rate ; Ribulose-1,5-bisphosphate carboxylase-oxygenase (Rubisco) ; Transgenic plant (tobacco antisense DNA)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Wild-type tobacco (Nicotiana tabacum L.) plants and transgenic tobacco transformed with antisense rbcS to decrease expression of ribulose-1,5-bisphosphate carboxylase-oxygenase (Rubisco; EC 4.1.1.39) were grown at 300 mol-m−2 · s−1 irradiance and 20° C at either 0.1, 0.7 or 5 mM NH4NO3. In high nitrogen (N), growth was reduced in parallel with the inhibition of photosynthesis when Rubisco was decreased by genetic manipulation. In limiting N, photosynthesis was reduced strongly when Rubisco was decreased by genetic manipulation, but growth was hardly affected. At all N levels, decreased expression of Rubisco led to a decrease in the amount of starch accumulated in the leaves. There was a large increase of the specific leaf area (SLA; leaf area maintained per unit dry weight in the leaf) in plants with decreased Rubisco. Increased SLA was associated with an increased inorganic and a decreased carbon contribution to leaf structural dry weight. The increased SLA represents a more efficient investment of photosynthate with respect to maximisation of leaf area and light interception, and partly compensates for the decreased rate of photosynthesis in plants with decreased expression of Rubisco. The changes of starch content and SLA were particularly large in limiting N, when growth rate was effectively independent of the rate of photosynthesis. Increased N availability led to a large increase of the shoot/ root ratio, but only a small increase in SLA. It is argued that N availability and the availability of photosynthate both regulate storage and allocation of biomass to optimize resource utilization, but achieve this via different mechanisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00195668
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 50
    Electronic Resource
    Electronic Resource
    Influence of the tobacco mosaic virus 30-kDa movement protein on carbon metabolism and photosynthate partitioning in transgenic tobacco plants (1993)
    Springer
    Planta 190 (1993), S. 88-96 
    Details
    ISSN: 1432-2048
    Keywords: Carbon allocation ; Movement protein ; Nicotiana ; Photosynthesis ; Plasmodesma ; Tobacco mosaic virus ; Transgenic tobacco
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transgenic tobacco (Nicotiana tabacum L.) plants expressing the 30-kDa movement protein of tobacco mosaic virus (TMV-MP) were employed to investigate the influence of a localized change in mesophyll-bundle sheath plasmodesmal size exclusion limit on photosynthetic performance and on carbon metabolism and allocation. Under conditions of saturating irradiance, tobacco plants expressing the TMV-MP were found to have higher photosynthetic CO2-response curves compared with vector control plants. However, this difference was significant only in the presence of elevated CO2 levels. Photosynthetic measurements made in the green-house, under endogenous growth conditions, revealed that there was little difference between TMV-MP-expressing and control tobacco plants. However, analysis of carbon metabolites within source leaves where a TMV-MP-induced increase in plasmodesmal size exclusion limit had recently taken place established that the levels of sucrose, glucose, fructose and starch were considerably elevated above those present in equivalent control leaves. Although expression of the TMV-MP did not alter total plant biomass, it reduced carbon allocation to the lower region of the stem and roots. This difference in biomass distribution was clearly evident in the lower root-to-shoot ratios for the TMV-MP transgenic plants. Microinjection (dye-coupling) studies established that the TMV-MP-associated reduction in photosynthate delivery (allocation) to the roots was not due to a direct effect on root cortical plasmodesmata. Rather, this change appeared to result from an alteration in phloem transport from young source leaves in which the TMV-MP had yet to exert its influence over plasmodesmal size exclusion limits. These results are discussed in terms of the rate-limiting steps involved in sucrose movement into the phloem.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00195679
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 51
    Electronic Resource
    Electronic Resource
    Light activation and molecular-mass changes of NAD(P)-glyceraldehyde 3-phosphate dehydrogenase of spinach and maize leaves (1993)
    Springer
    Planta 190 (1993), S. 313-319 
    Details
    ISSN: 1432-2048
    Keywords: Calvin cycle ; Glyceraldehyde 3-phosphate dehydrogenase, NAD(P)-dependent ; Photosynthesis ; Spinacia ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Light modulation of chloroplast glyceraldehyde 3-phosphate dehydrogenase (NAD(P)-GAPDH; EC 1.2.1.13) has been investigated. Complete activation of NADPH-dependent activity is achieved at 25 W.m−2 photosynthetically active radiation in spinach (Spinacia oleracea L.) and 100 W.m−2 in maize (Zea mays L.) leaves. Light activation is stronger in spinach (fivefold on average) than in maize (twofold), which shows higher “dark” activity. The NADH dependent activity does not change appreciably. Several substrate activators can simulate in vitro the light effect with recovery of latent NADPH-dependent activity of spinach enzyme, but they are almost inactive with maize enzyme. A mixture of activators has been devised to fully activate the spinach enzyme under most conditions. The NAD(P)-GAPDH protein can be resolved by rapid gel filtration (fast protein liquid chromatography) into three conformers which have different molecular masses according to the light conditions. Enzyme from darkened leaves or chloroplasts, or dichlorophenyl-1,1-dimethylurea-treated chloroplasts is mainly a 600-kDa regulatory form with low NADPH-dependent activity relative to NADH-activity. Enzyme from spinach leaves or chloroplasts during photosynthesis is mainly a 300-kDa oligomer, which along with the 600-kDa form also occurs in leaves of darkened maize. The conformer of illuminated maize leaves is mainly a 160-kDa species. Results are consistent with a model of NAD(P)-GAPDH freely interconvertible between protomers of the 160-kDa (or 300-kDa intermediate) form with high NADPH-activity, produced in the light by the action of thioredoxin and activating metabolites (spinach only), and a regulatory 600-kDa conformer with lower NADPH-activity produced in darkness or when photosynthesis is inhibited. This behavior is reminiscent of the in-vitro properties of purified enzyme; therefore, it seems unlikely that NAD(P)-GAPDH in the chloroplast is part of a stable multienzyme complex or is bound to membranes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00196959
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 52
    Electronic Resource
    Electronic Resource
    Evidence for 18O labeling of photorespiratory CO2 in photoautotrophic cell cultures of higher plants illuminated in the presence of 18O2 (1993)
    Springer
    Planta 190 (1993), S. 407-414 
    Details
    ISSN: 1432-2048
    Keywords: Euphorbia (photorespiration) ; Glycolate pathway ; Oxygen exchange ; Photorespiration ; Photosynthesis ; Post-illumination burst
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The 18O-enrichment of CO2 produced in the light or during the post-illumination burst was measured by mass spectrometry when a photoautotrophic cell suspension of Euphorbia characias L. was placed in photorespiratory conditions in the presence of molecular 18O2. The only 18O-labeled species produced was C18O16O; no C18O18O could be detected. Production of C18O16O ceased after addition of two inhibitors of the photosynthetic carbon-oxidation cycle, aminooxyacetate or aminoacetonitrile, and was inhibited by high levels of CO2. The average enrichment during the post-illumination burst was estimated to be 46 ± 15% of the enrichment of the O2 present during the preceding light period. Addition of exogenous carbonic anhydrase, by catalyzing the exchange between CO2 and H2O, drastically diminished the 18O-enrichment of the produced CO2. The very low carbonio-anhydrase level of the photoautotrophic cell suspension probably explains why the 18O labeling of photorespiratory CO2 could be observed for the first time. These data allow the establishment of a direct link between O2 consumption and CO2 production in the light, and the conclusion that CO2 produced in the light results, at least partially, from the mitochondrial decarboxylation of the glycine pool synthesized through the photosynthetic carbon-oxidation cycle. Analysis of the C18O16O and CO2 kinetics provides a direct and reliable way to assess in vivo the real contribution of photorespiratory metabolism to CO2 production in the light.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00196970
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 53
    Electronic Resource
    Electronic Resource
    Evidence for the functioning of photosynthetic CO2-concentrating mechanisms in lichens containing green algal and cyanobacterial photobionts (1993)
    Springer
    Planta 191 (1993), S. 57-70 
    Details
    ISSN: 1432-2048
    Keywords: Carbon dioxide concentrating mechanism ; Carbonic anhydrase ; Cyanobacterium ; Green alga ; Lichens ; Photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The photosynthetic properties of a range of lichens containing both green algal (11 species) and cyanobacterial (6 species) photobionts were examined with the aim of determining if there was clear evidence for the operation of a CO2-concentrating mechanism (CCM) within the photobionts. Using a CO2-gas-exchange system, which allowed resolution of fast transients, evidence was obtained for the existence of an inorganic carbon pool which accumulated in the light and was released in the dark. The pool was large (500–1000 nmol · mg Chl) in cyanobacterial lichens and about tenfold smaller in green algal lichens. In Hypogymnia physodes (L.) Nyl., which contains the green alga Trebouxia jamesii, a small inorganic carbon pool was rapidly formed in the light. Carbon dioxide was released from this pool into the gas phase upon darkening within about 20 s when photosynthesis was inhibited by the carbon-reduction-cycle inhibitor glycolaldehyde. In the absence of this inhibitor, release appeared to be obscured by carboxylation of ribulose bisphosphate. The kinetics of CO2 uptake and release were monophasic. The operation of an active CCM could be distinguished from passive accumulation and release accompanying the reversible light-dependent alkalization of the stroma by the presence of saturation characteristics with respect to external CO2. In Peltigera canina (L.) Willd., which contains the cyanobacterium Nostoc sp., a larger CO2 pool was taken up over a longer period in the light and the release of this pool in the dark was slow, lasting 3–5 min. This pool also accumulated in the presence of glycolaldehyde, and under these conditions the CO2 release was biphasic. In both species, photosynthesis at low CO2 was inhibited by the carbonic-anhydrase inhibitor ethoxyzolamide (EZ). Inhibition could be reversed fully or to a considerable extent by high CO2. In Peltigera, EZ decreased both the accumulation of the CO2 pool by the CCM and the rate of photosynthesis. Free-living cultures of Nostoc sp. showed a similar effect of EZ on photosynthesis, although it was more dramatic than that seen with the lichen thalli. In contrast, in Hypogymnia, EZ actually increased the size of the CO2 pool, although it inhibited photosynthesis. This effect was also seen when glycolaldehyde was present together with EZ. Surprisingly, EZ did not alter the kinetics of either CO2 uptake or release. Taken together, the evidence indicates the operation in cyanobacterial lichens of a CCM which is capable of considerable elevation of internal CO2 and is similar to that reported for free-living cyanobacteria. The CCM of green algal lichens accumulates much less CO2 and is probably less effective than that which operates in cyanobacterial lichens.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00240896
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 54
    Electronic Resource
    Electronic Resource
    Immunocytochemical localization of phosphoenolpyruvate carboxylase and photosynthetic gas-exchange characteristics in ears of Triticum durum Desf. (1993)
    Springer
    Planta 191 (1993), S. 507-514 
    Details
    ISSN: 1432-2048
    Keywords: Ear bract ; Kernel ; Phosphoenolpyruvate carboxylase (immunolocalization) ; Photosynthesis ; Triticum (photosynthesis)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The presence and distribution of phosphoenolpyruvate carboxylase (PEPCase) in the glumes and immature grains of durum wheat (Triticum durum Desf.) were studied by electron-microscopical immunolabeling of PEPCase with polyclonal antibodies followed by protein A-gold. Plants were grown under mediterranean field conditions and samples were obtained two weeks after anthesis. In the kernels, high gold label was associated with the unstained areas of the protein bodies of aleurone cells, whereas labeling in the cytoplasm and chloroplasts of the pericarp was slight, although significantly above the background. In the glumes, high gold label was only located in cytoplasmic granules (vesicles) of the mesophyll cells, although labeling in the cytoplasm and chloroplasts was also significantly above the background. These observations in immature kernels and glumes are in accordance with the anaplerotic role of this enzyme, as evidenced in C3 plants. Measurements of apparent photosynthesis and its O2 dependence and CO2 compensation concentration were made on ears and flag leaves of durum wheat. In addition, an analog of phosphoenolpyruvate, 3,3-dichloro-2-dihydroxy-phosphinoylmethyl-2-propenoate, was used to inhibit PEPCase and, thereby, to assess the contribution of the PEPCase to photosynthesis in detached ears. There was no effect of the inhibitor on the apparent photosynthesis of ears. Whereas inhibition of apparent photosynthesis by 210 mL · L−1 O2 in flag leaves was typical of C3 species, inhibition in ears was even greater. The CO2 compensation concentrations in different ear parts were similar to or higher than in flag leaves and the O2 dependence was also comparable (about 70%). Therefore, gas-exchange data give further support to the assumption that a C4 cycle is absent or limited to very low rates in ears of durum wheat.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00195752
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 55
    Electronic Resource
    Electronic Resource
    Effect of vanadate on photosynthesis and the ATP/ADP ratio in low-CO2-adapted Chlamydomonas reinhardtii cells (1993)
    Springer
    Planta 192 (1993), S. 46-51 
    Details
    ISSN: 1432-2048
    Keywords: ATPase ; Carbon concentrating mechanism ; Carbonic anhydrase ; Chlamydomonas ; Photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have assessed the effect of vanadate as an inhibitor of plasma-membrane ATPase on photosynthesis and the ATP/ADP ratio in Chlamydomonas reinhardtii CW-92 (a mutant strain lacking a cell wall). This effect was compared in low-CO2-adapted cells grown in media bubbled with air containing 400 or 70 μL · L−1 CO2. Evidence is presented indicating that cells grown at 70 μL · L−1 CO2 have a higher rate of photosynthetic O2 evolution than cells grown at 400 μL · L−1 CO2, at limiting carbon concentrations. Extracellular and intracellular carbonic-anhydrase activities were, however, similar in cells grown in both of the low-carbon conditions. Vanadate inhibited, to a different extent, the HCO 3 − -dependent O2 evolution in cells grown at 400 and 70 μL · L−1 CO2. At 400 μM vanadate, inhibition reached 70–75% in cells grown at 400 μL · L−1 but only 50% in those grown at 70 μL · L−1 CO2. The ATP/ADP ratios determined with and without vanadate at limiting concentrations of dissolved inorganic carbon indicated that more ATP was hydrolysed in algae grown at 70 μL · L−1 than in those grown at 400 μL · L−1 CO2. We conclude that the maximal capacity to accumulate dissolved inorganic carbon is inversely related to the CO2 concentration in the medium. Activation and — or synthesis of vanadate-sensitive ATPase may be the major explanation for the higher capacity for HCO 3 − -dependent O2 evolution in cells grown under limited CO2 concentrations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00198691
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 56
    Electronic Resource
    Electronic Resource
    Environmental effects on circadian rhythms in photosynthesis and stomatal opening (1993)
    Springer
    Planta 189 (1993), S. 369-376 
    Details
    ISSN: 1432-2048
    Keywords: Circadian rhythm ; Phaseolus ; Photosynthesis ; Stomate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Persistent circadian rhythms in photosynthesis and stomatal opening occurred in bean (Phaseolus vulgaris L.) plants transferred from a natural photoperiod to a variety of constant conditions. Photosynthesis, measured as carbon assimilation, and stomatal opening, as conductance to water vapor, oscillated with a freerunning period close to 24 h under constant moderate light, as well as under light-limiting and CO2-limiting conditions. The rhythms damped under constant conditions conducive to high photosynthetic rates, as did rates of carbon assimilation and stomatal conductance, and this damping correlated with the accumulation of carbohydrate. No rhythm in respiration occurred in plants transferred to constant darkness, and the rhythm in stomatal opening damped rapidly in constant darkness. Damping of rhythms also occurred in leaflets exposed to constant light and CO2-free air, demonstrating that active photosynthesis and not simply light was necessary for sustained expression of these rhythms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00194433
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 57
    Electronic Resource
    Electronic Resource
    Activation of spinach chloroplast glyceraldehyde 3-phosphate dehydrogenase: effect of glycerate 1,3-bisphosphate (1993)
    Springer
    Planta 190 (1993), S. 320-326 
    Details
    ISSN: 1432-2048
    Keywords: Calvin cycle ; Glyceraldehyde 3-phosphate dehydrogenase, NAD(P)-dependent ; Glycerate 1,3-bisphosphate ; Photosynthesis ; Spinacia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Spinach (Spinacia oleracea L.) chloroplast NAD(P)-dependent glyceraldehyde 3-phosphate dehydrogenase (NAD(P)-GAPDH; EC 1.2.1.13) was purified. The association state of the protein was monitored by fast protein liquid chromatography-Superose 12 gel filtration. Protein chromatographed in the presence of NADP+ and dithiothreitol consisted of highly NADPH-active protomers of 160 kDa; otherwise, it always consisted of a 600-kDa oligomer (regulatory form) favoured by the addition of NAD+ in buffers and with low NADPH-dependent activity (ratio of activities with NADPH versus NADH of 0.2–0.4). Glycerate 1,3-bisphosphate (BPGA) was prepared enzymatically using rabbit-muscle NAD-GAPDH, and purified. Among known modulators of spinach NAD(P)-GAPDH, BPGA is the most effective on a molar basis in stimulating NADPH-activity of “dark” chloroplast extracts and purified NAD(P)-GAPDH (activation constant, K a= 12 μM). It also causes the enzyme to dissociate into 160-kDa protomers. The K m of BPGA both with NADPH or NADH as coenzyme is 4–7 μM. NAD+ and NADH are inhibitory to the activation process induced by BPGA. This compound, together with NADP(H) and ATP belongs to a group of substrate-modifiers of the NADPH-activity and conformational state of spinach NAD(P)-GAPDH, all characterized by K a values three- to tenfold higher than the K m. Since NADP(H) is largely converted to NAD(H) in darkened chloroplasts Heineke et al. 1991, Plant Physiol. 95, 1131–1137, it is proposed that NAD+ promotes NAD(P)-GAPDH association into a regulatory conformer with low NADPH-activity during dark deactivation. The process is reversed in the light by BPGA and other substrate-modifiers whose concentration increases during photosynthesis, in addition to reduced thioredoxin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00196960
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 58
    Electronic Resource
    Electronic Resource
    Decreased ribulose-1,5-bisphosphate carboxylase-oxygenase in transgenic tobacco transformed with “antisense” rbcS (1993)
    Springer
    Planta 190 (1993), S. 332-345 
    Details
    ISSN: 1432-2048
    Keywords: Light climate ; Nicotiana (photosynthesis) ; Photosynthesis ; Ribulose 1,5-bisphosphate carboxylase-oxygenase ; Transgenic plant (tobacco, antisense DNA)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Tobacco (Nicotiana tabacum L.) plants transformed with ‘antisense’ rbcS to decrease the expression of ribulose-1,5-bisphosphate carboxylase-oxygenase (Rubisco) have been used to investigate the contribution of Rubisco to the control of photosynthesis in plants growing at different irradiances. Tobacco plants were grown in controlled-climate chambers under ambient CO2 at 20°C at 100, 300 and 750 μmol·m−2·s−1 irradiance, and at 28°C at 100, 300 and 1000 μmol·m−2·s−1 irradiance. (i) Measurement of photosynthesis under ambient conditions showed that the flux control coefficient of Rubisco (C infRubisco supA ) was very low (0.01–0.03) at low growth irradiance, and still fairly low (0.24–0.27) at higher irradiance. (ii) Short-term changes in the irradiance used to measure photosynthesis showed that C infRubisco supA increases as incident irradiance rises, (iii) When low-light (100 μmol·m−2·s−1)-grown plants are exposed to high (750–1000 μmol·m−2·s−1) irradiance, Rubisco is almost totally limiting for photosynthesis in wild types. However, when high-light-grown leaves (750–1000 μmol·m−2·s−1) are suddenly exposed to high and saturating irradiance (1500–2000 μmol·m−2·s−1), C infRubisco supA remained relatively low (0.23–0.33), showing that in saturating light Rubisco only exerts partial control over the light-saturated rate of photosynthesis in “sun” leaves; apparently additional factors are co-limiting photosynthetic performance, (iv) Growth of plants at high irradiance led to a small decrease in the percentage of total protein found in the insoluble (thylakoid fraction), and a decrease of chlorophyll, relative to protein or structural leaf dry weight. As a consequence of this change, high-irradiance-grown leaves illuminated at growth irradiance avoided an inbalance between the “light” reactions and Rubisco; this was shown by the low value of C infRubisco supA (see above) and by measurements showing that non-photochemical quenching was low, photochemical quenching high, and NADP-malate dehydrogenase activation was low at the growth irradiance. In contrast, when a leaf adapted to low irradiance was illuminated at a higher irradiance, Rubisco exerted more control, non-photochemical quenching was higher, photochemical quenching was lower, and NADP-malate dehydrogenase activation was higher than in a leaf which had grown at that irradiance. We conclude that changes in leaf composition allow the leaf to avoid a one-sided limitation by Rubisco and, hence, overexcitation and overreduction of the thylakoids in high-irradiance growth conditions, (v) ‘Antisense’ plants with less Rubisco contained a higher content of insoluble (thylakoid) protein and chlorophyll, compared to total protein or structural leaf dry weight. They also showed a higher rate of photosynthesis than the wild type, when measured at an irradiance below that at which the plant had grown. We propose that N-allocation in low light is not optimal in tobacco and that genetic manipulation to decrease Rubisco may, in some circumstances, increase photosynthetic performance in low light.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00196962
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 59
    Electronic Resource
    Electronic Resource
    Bicarbonate uptake in the marine macroalga Ulva sp. is inhibited by classical probes of anion exchange by red blood cells (1993)
    Springer
    Planta 191 (1993), S. 34-40 
    Details
    ISSN: 1432-2048
    Keywords: Anion exchange(r) (band 3) protein ; Bicarbonate uptake ; Photosynthesis ; Protein (band 3) ; Ulva(photosynthesis)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We demonstrate in this work that HCO inf3 sup− uptake in the marine macroalga Ulva sp. features functional resemblances to anion transport mediated by anion exchangers of mammalian cell membranes. The evidence is based on (i) competitive inhibition of photosynthesis by the classical red-blood-cell anion-exchange blockers 4,4′-dinitrostilbene-2,2′-disulfonate and 4-nitro-4′-isothiocyanostilbene-2,2′-disulfonate under conditions where HCO inf3 sup− , but not CO2, was the inorganic carbon form taken up; (ii) inhibition of HCO inf3 − uptake by pyridoxal phospate, indicating the involvement of lysine residues in the binding/translocation of HCO inf3 sup− ; and (iii) inhibition of HCO inf3 sup− (but not of CO2) uptake by exofacial trypsin treatments, indicating the functional involvement of a plasmalemma protein. It is suggested that HCO inf3 sup− uptake mediated by such a putative anion transporter can be a fundamental step in providing inorganic carbon for the CO2-concentrating system of marine marcoalgae in an environment where the HCO inf3 sup− concentration is high, but the CO2 concentration and rates of uncatalyzed HCO inf3 sup− dehydration are low.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00240893
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 60
    Electronic Resource
    Electronic Resource
    Temperate rainforest lichens in New Zealand: high thallus water content can severely limit photosynthetic CO2 exchange (1993)
    Springer
    Oecologia 95 (1993), S. 303-313 
    Details
    ISSN: 1432-1939
    Keywords: Lichen ; Water content ; Photosynthesis ; Rainforest ; Diffusive resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract CO2 exchange rate in relation to thallus water content (WC, % of dry weight) was determined for 22 species of lichens, mainly members of the genera Pseudocyphellaria and Sticta, from a temperate rainforest, Urewere National Park, New Zealand. All data were obtained in the field, either using a standard technique in which the lichens were initially wetted (soaked or sprayed, then shaken) and allowed to slowly dry, or from periodic measurements on samples that were continuously exposed in their natural habitat. A wide range of WC was found, with species varying from 357 to 3360% for maximal WC in the field, and from 86 to 1300% for optimal WC for photosynthesis. Maximal WC for lichens, wetted by the standard technique, were almost always much less than the field maxima, due to the presence of water on the thalli. The relationships between CO2 exchange rate and WC could be divided into four response types based on the presence, and degree, of depression of photosynthesis at high WC. Type A lichens showed no depression, and Type B only a little at maximal WC. Type C had a very large depression and, at the highest WC, CO2 release could occur even in the light. Photosynthetic depression commenced soon after optimal WC was reached. Type D lichens showed a similar depression but the response curve had an inflection so that net photosynthesis was low but almost constant, and never negative, at higher WC. There was little apparent relationship between lichen genus or photobiont type and the response type. It was shown that high WC does limit photosynthetic CO2 uptake under natural conditions. Lichens, taken directly from the field and allowed to dry under controlled conditions, had net photosynthesis rates that were initially strongly inhibited but rose to an optimum, before declining at low WC. The limiting effects of high WC were clearly shown when, under similar light conditions, severe photosynthetic depression followed a brief, midday, rain storm. Over the whole measuring period the lichens were rarely at their optimal WC for photosynthesis, being mostly too wet or, occasionally, too dry. Photosynthetic performance by the lichens exposed in the field was similar to that expected from the relationship between the photosynthetic rate and WC established by the standard procedure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00320981
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 61
    Electronic Resource
    Electronic Resource
    Canopy structure and vertical patterns of photosynthesis and related leaf traits in a deciduous forest (1993)
    Springer
    Oecologia 96 (1993), S. 169-178 
    Details
    ISSN: 1432-1939
    Keywords: Acer saccharum ; Photosynthesis ; Forest canopy ; Sugar maple ; Nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Canopy structure and light interception were measured in an 18-m tall, closed canopy deciduous forest of sugar maple (Acer saccharum) in southwestern Wisconsin, USA, and related to leaf structural characteristics, N content, and leaf photosynthetic capacity. Light attenuation in the forest occurred primarily in the upper and middle portions of the canopy. Forest stand leaf area index (LAI) and its distribution with respect to canopy height were estimated from canopy transmittance values independently verified with a combined leaf litterfall and point-intersect method. Leaf mass, N and A max per unit area (LMA, N/area and A max/area, respectively) all decreased continuously by over two-fold from the upper to lower canopy, and these traits were strongly correlated with cumulative leaf area above the leaf position in the canopy. In contrast, neither N concentration nor A max per unit mass varied significantly in relation to the vertical canopy gradient. Since leaf N concentration showed no consistent pattern with respect to canopy position, the observed vertical pattern in N/area is a direct consequence of vertical variation of LMA. N/area and LMA were strongly correlated with A max/area among different canopy positions (r2=0.81 and r2=0.66, respectively), indicating that vertical variation in area-based photosynthetic capacity can also be attributed to variation in LMA. A model of whole-canopy photosynthesis was used to show that observed or hypothetical canopy mass distributions toward higher LMA (and hence higher N/area) in the upper portions of the canopy tended to increase integrated daily canopy photosynthesis over other LMA distribution patterns. Empirical relationships between leaf and canopy-level characteristics may help resolve problems associated with scaling gas exchange measurements made at the leaf level to the individual tree crown and forest canopy-level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00317729
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 62
    Electronic Resource
    Electronic Resource
    Photosynthetic induction responses of two rainforest tree species in relation to light environment (1993)
    Springer
    Oecologia 96 (1993), S. 193-199 
    Details
    ISSN: 1432-1939
    Keywords: Costa Rica ; Hemispherical photography ; Photosynthesis ; Rain forest ; Sunflecks
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Photosynthetic induction of in situ saplings of two Costa Rican rainforest tree species wre compared in relation to their light environment, using infrared gas analysis and hemispherical photography. The species studied were Dipteryx panamensis, a climax species found in bright microsites, and Cecropia obtusifolia, a pioneer species. In the morning, when leaves were most responsive, induction time necessary to reach 90% of the lightsaturated rate of photosynthesis was on average 16 min for Dipteryx and 10 min for Cecropia. However, induction times for both species increased in the afternoon resulting in shorter daily average induction times for Dipteryx than for Cecropia. Dipteryx also maintained higher levels of induction for a longer period under low light conditions than did Cecropia. The two species differed in the way they adjusted to light availability. Dipteryx saplings growing in shady sites had faster rates of induction than saplings growing in bright sites, with no difference in light-saturated photosynthetic rate. In contrast, Cecropia saplings growing in bright sites had higher light-saturated photosynthetic rates than saplings growing in shady sites, with no difference in rates of induction. Dipteryx appears to exploit temporal variation in light availability by refining the quickness of the induction response to the light environment, while Cecropia adjusts its scale of exploitation by realizing a higher lightsaturated photosynthetic rate in sites of higher light.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00317732
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 63
    Electronic Resource
    Electronic Resource
    Photoinhibition as a control on photosynthesis and production of Sphagnum mosses (1993)
    Springer
    Oecologia 96 (1993), S. 200-207 
    Details
    ISSN: 1432-1939
    Keywords: Photosynthesis ; Production ; Sphagnum moss ; Photoinhibition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of high light intensity on photosynthesis and growth of Sphagnum moss species from Alaskan arctic tundra was studied under field and laboratory conditions. Field experiments consisted of experimental shading of mosses at sites normally exposed to full ambient irradiance, and removal of the vascular plant canopy from above mosses in tundra water track habitats. Moss growth was then monitored in the experimental plots and in adjacent control areas for 50 days from late June to early August 1988. In shaded plots total moss growth was 2–3 times higher than that measured in control plots, while significant reductions in moss growth were found in canopy removal plots. The possibility that photoinhibition of photosynthesis might occur under high-light conditions and affect growth was studied under controlled laboratory conditions with mosses collected from the arctic study site, as well as from a temperate location in the Sierra Nevada, California. After 2 days of high-light treatment (800 μmol photons m−2 s−1) in a controlled environmental chamber, moss photosynthetic capacity was significantly lowered in both arctic and temperate samples, and did not recover during the 14-day experimental period. The observed decrease in photosynthetic capacity was correlated (r 2=0.735, P〈0.001) with a decrease in the ratio of variable to maximum chlorophyll fluorescence (F v/F m) in arctic and temperate mosses. This relationship indicates photoinhibition of photosynthesis in both arctic and temperate mosses at even moderately high light intensities. It is suggested that susceptibility to photoinhibition and failure to photoacclimate to higher light intensities in Sphagnum spp. may be related to low tissue nitrogen levels in these exclusively ombrotrophic plants. Photoinhibition of photosynthesis leading to lowered annual carbon gain in Sphagnum mosses may be an important factor affecting CO2 flux at the ecosystem level, given the abundance of these plants in Alaskan tussock tundra.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00317733
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 64
    Electronic Resource
    Electronic Resource
    Relative growth rate in relation to physiological and morphological traits for northern hardwood tree seedlings: species, light environment and ontogenetic considerations (1993)
    Springer
    Oecologia 96 (1993), S. 219-231 
    Details
    ISSN: 1432-1939
    Keywords: Relative growth rate ; Leaf allocation ; Photosynthesis ; Respiration ; Ontogeny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The influence of ontogeny, light environment and species on relationships of relative growth rate (RGR) to physiological and morphological traits were examined for first-year northern hardwood tree seedlings. Three Betulaceae species (Betula papyrifera, Betula alleghaniensis and Ostrya virginiana) were grown in high and low light and Quercus rubra and Acer saccharum were grown only in high light. Plant traits were determined at four ages: 41, 62, 83 and 104 days after germination. In high light (610 μmol m−2 s−1 PPFD), across species and ages, RGR was positively related to the proportion of the plant in leaves (leaf weight ratio, LWR; leaf area ratio, LAR), in situ rates of average canopy net photosynthesis (A) per unit mass (Amass) and per unit area (Aarea), and rates of leaf, stem and root respiration. In low light (127 μmol m−2 s−1 PPFD), RGR was not correlated with Amass and Aarea whereas RGR was positively correlated with LAR, LWR, and rates of root and stem respiration. RGR was negatively correlated with leaf mass per area in both high and low light. Across light levels, relationships of CO2 exchange and morphological characteristics with RGR were generally weaker than within light environments. Moreover, relationships were weaker for plant parameters containing a leaf area component (leaf mass per area, LAR and Aarea), than those that were solely mass-based (respiration rates, LWR and Amass). Across light environments, parameters incorporating the proportion of the plant in leaves and rates of photosynthesis explained a greater amount of variation in RGR (e.g. LWR*Amass, R2=0.64) than did any single parameter related to whole-plant carbon gain. RGR generally declined with age and mass, which were used as scalars of ontogeny. LWR (and LAR) also declined for seven of the eight species-light treatments and A declined in four of the five species in high light. Decreasing LWR and A with ontogeny may have been partially responsible for decreasing RGR. Declines in RGR were not due to increased respiration resulting from an increase in the proportion of solely respiring tissue (roots and stems). In general, although LWR declined with ontogeny, specific rates of leaf, stem, and root respiration also decreased. The net result was that whole-plant respiration rates per unit leaf mass decreased for all eight treatments. Identifying the major determinants of variation in growth (e.g. LWR*Amass) across light environments, species and ontogeny contributes to the establishment of a framework for exploring limits to productivity and the nature of ecological success as measured by growth. The generality of these relationships both across the sources of variation we explored here and across other sources of variation in RGR needs further study.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00317735
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 65
    Electronic Resource
    Electronic Resource
    Coordination theory of leaf nitrogen distribution in a canopy (1993)
    Springer
    Oecologia 93 (1993), S. 63-69 
    Details
    ISSN: 1432-1939
    Keywords: Canopy structure ; Coordination ; Nitrogen allocation ; Optimization ; Photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract It has long been observed that leaf nitrogen concentrations decline with depth in closed canopies in a number of plant communities. This phenomenon is generally believed to be related to a changing radiation environment and it has been suggested by some researchers that plants allocate nitrogen in order to optimize total whole canopy photosynthesis. Although optimization theory has been successfully utilized to describe a variety of physiological and ecological phenomena, it has some shortcomings that are subject to criticism (e.g., time constraints, oversimplifications, lack of insights, etc.). In this paper we present an alternative to the optimization theory of plant canopy nitrogen distribution, which we term coordination theory. We hypothesize that plants allocate nitrogen to maintain a balance between two processes, each of which is dependent on leaf nitrogen content and each of which potentially limits photosynthesis. These two processes are defined as Wc, the Rubiscolimited rate of carboxylation, and Wj, the electron transport-limited rate of carboxylation. We suggest that plants allocate nitrogen differentially to, leaves in different canopy layers in such a way that Wc and Wj remain roughly balanced. In this scheme, the driving force for the allocation of nitrogen within a canopy is the difference between the leaf nitrogen content that is required to bring Wc and Wj into balance and the current nitrogen content. We show that the daily carbon assimilation of a canopy with a nitrogen distribution resulting from this internal coordination of Wc and Wj is very similar to that obtained using optimization theory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00321192
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 66
    Electronic Resource
    Electronic Resource
    Phenotypic plasticity in response to nitrate supply of an inherently fast-growing species from a fertile habitat and an inherently slow-growing species from an infertile habitat (1993)
    Springer
    Oecologia 96 (1993), S. 548-554 
    Details
    ISSN: 1432-1939
    Keywords: Biomass allocation ; Nitrogen supply ; Phenotypic plasticity ; Photosynthesis ; Root distribution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The aim of the present study was to investigate possible differences in plasticity between a potentially fast-growing and a potentially slow-growing grass species. To this end, Holcus lanatus (L.) and Deschampsia flexuosa (L.) Trin., associated with fertile and infertile habitats, respectively, were grown in sand at eight nitrate concentrations. When plants obtained a fresh weight of approximately 5 g, biomass allocation, specific leaf area, the rate of net photosynthesis, the organic nitrogen concentration of various plant parts and the root weight at different soil depths were determined. There were linear relationships between the morphological and physiological features studied and the In-transformed nitrate concentration supplied, except for the specific leaf area and root nitrogen concentration of H. lanatus, which did not respond to the nitrate concentration. The root biomass of H. lanatus was invariably distributed over the soil layers than that of D. flexuosa. However, D. flexuosa allocated more root biomass to lower soil depths with decreasing nitrate concentration, in contrast to H. lanatus, which did not respond. The relative response to nitrate supply, i.e. the value of a character at a certain nitrate level relative to the value of that character at the highest nitrate supply, was used as a measure for plasticity. For a number of parameters (leaf area ratio, root weight ratio, root nitrogen concentration, vertical root biomass distribution and rate of net photosynthesis per unit leaf weight) the potentially slow-growing D. flexuosa exhibited a higher phenotypic plasticity than the potentially fast-growing H. lanatus. These findings are in disagreement with current literature. Possible explanations for this discrepancy are discussed in terms of differences in experimental approach as well as fundamental differences in specific traits between fast- and slow-growing grasses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00320512
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 67
    Electronic Resource
    Electronic Resource
    Growth, biomass distribution and CO2 exchange of northern hardwood seedlings in high and low light: relationships with successional status and shade tolerance (1993)
    Springer
    Oecologia 94 (1993), S. 7-16 
    Details
    ISSN: 1432-1939
    Keywords: Relative growth rate ; Photosynthesis ; Respiration ; Biomass distribution ; Shade tolerance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The physiology, morphology and growth of first-year Betula papyrifera Marsh., Betula alleghaniensis Britton, Ostrya virginiana (Mill.) K. Koch, Acer saccharum Marsh., and Quercus rubra L. seedlings, which differ widely in reported successional affinity and shade tolerance, were compared in a controlled high-resource environment. Relative to late-successional, shade-tolerant Acer and Ostrya species, early-successional, shade-intolerant Betula species had high relative growth rates (RGR) and high rates of photosynthesis, nitrogen uptake and respiration when grown in high light. Fire-adapted Quercus rubra had intermediate photosynthetic rates, but had the lowest RGR and leaf area ratio and the highest root weight ratio of any species. Interspecific variation in RGR in high light was positively correlated with allocation to leaves and rates of photosynthesis and respiration, and negatively related to seed mass and leaf mass per unit area. Despite higher respiration rates, early-successional Betula papyrifera lost a lower percentage of daily photosynthetic CO2 gain to respiration than other species in high light. A subset comprised of the three Betulaceae family members was also grown in low light. As in high light, low-light grown Betula species had higher growth rates than tolerant Ostrya virainiana. The rapid growth habit of sarly-successional species in low light was associated with a higher proportion of biomass distributed to leaves, lower leaf mass per unit area, a lower proportion of biomass in roots, and a greater height per unit stem mass. Variation in these traits is discussed in terms of reported species ecologies in a resource availability context.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00317294
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 68
    Electronic Resource
    Electronic Resource
    Photosynthesis and water-use efficiency in pinyon-juniper communities along an elevation gradient in northern New Mexico (1993)
    Springer
    Oecologia 94 (1993), S. 95-101 
    Details
    ISSN: 1432-1939
    Keywords: δ13C ; Nutrient-use efficiency ; Photosynthesis ; Pinyon-juniper ; Water-use efficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We investigated plant ecophysiological response to fertilization of selected sites along an elevation gradient in a pinyon-juniper woodland. Plant density and species composition followed typical patterns for pinyon-juniper woodlands over this gradient, with a sparse juniper (Juniperus monosperma (Engelm.) Sarg.)-grassland community at the lowest elevation and gradually increasing total canopy cover and pinyon (Pinus edulis Engelm.) cover with elevation. Carbon isotope analysis showed that both tree species had higher water-use efficiency (WUE) at the lowest, and presumably driest, sites. Over most of the gradient, however, it appeared that changes in stand density compensated for changes in water availability. Contrary to initial hypotheses, the more drought-tolerant juniper did not demonstrate significantly greater WUE than pinyon, although it maintained positive carbon gain at lower predawn xylem pressure potentials than pinyon. In pinyon, both A max and WUE increased with increasing N concentration in tissues. Pinyon needles also demonstrated declining nitrogen-use efficiency with age. There was no relationship between tissue N and either A max or WUE measured at A max in juniper, although δ13C analysis indicated that WUE increased in juniper with increased N availability. Results from this study suggest that plasticity in plant physiological processes could result in nonlinear responses of organic matter production to climate change, and therefore must be accounted for in ecosystem models.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00317308
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 69
    Electronic Resource
    Electronic Resource
    Gas exchange characteristics and nitrogen relations of two Mediterranean root hemiparasites:Bartsia trixago andParentucellia viscosa (1993)
    Springer
    Oecologia 95 (1993), S. 145-151 
    Details
    ISSN: 1432-1939
    Keywords: Photosynthesis ; Nitrogen ; Parasitic angiosperm ; Gas exchange ; Leaf conductance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Plant height, light-saturated rates of photosynthesis (A max) and foliar nitrogen concentration (N 1) were measured forBartsia trixago under field conditions in Mallorca. All three variables were postively correlated, and were also positively related to the abundance of nitrogen-fixing legumes in the associated vegetation (putative host species).A max forB. trixago ranged from 7.7 to 18.8 μmol m-2 s-1; similar rates were measured for a second hemiparasiteParentucellia viscosa, and both species were within the range of rates measured for six putative hosts (10.6–19.2 μmol m-2 s-1). Fertilization of unattachedB. trixago plants with inorganic nitrogen (ammonium nitrate) elicited neither the growth nor the photosynthetic responses observed in plants considered to be parasitic on legumes and in receipt of an enriched organic nitrogen supply. Both hemiparasites had high diurnal leaf conductances (g s) (469–2291 mmol m-2 s-1) and were at the upper end of the range of those measured in putative hosts (409–879 mmol m-2 s-1). In contrast with the latter, high nocturnal rates ofg s were also recorded for the two hemiparasites (517–1862 mmol m-2 s-1). There was no clear relationship between eitherA max orN 1 and eitherg s, transpiration (E) or water use efficiency (A max/E) inB. trixago plants. The economics of water loss appear to be independent of both the supply of nitrogen from the host and autotrophic carbon fixation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00649518
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 70
    Electronic Resource
    Electronic Resource
    Photosynthetic characteristics of a giant alpine plant, Rheum nobile Hook. f. et Thoms. and of some other alpine species measured at 4300 m, in the Eastern Himalaya, Nepal (1993)
    Springer
    Oecologia 95 (1993), S. 194-201 
    Details
    ISSN: 1432-1939
    Keywords: Alpine plants ; Himalaya ; Monsoon ; Nitrogen ; Photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The photosynthetic characteristics of a giant alpine plant, Rheum nobile Hook. f. et Thoms. and of some other alpine species were studied in situ at 4300 m, in the Eastern Himalaya, Nepal, during the summer monsoon season. Although rainy and overcast weather was predominant, the daytime photon flux density (400–700 nm) ranged from 300 to 500 μmol quanta m-2 s-1. Under such conditions, the temperature of leaves of R. nobile ranged from 10 to 14°C, and the rate of photosynthetic CO2 exchange ranged from 10 to 16 μmol CO2 m-2 s-1. The ratios of the maximum rate of photosynthetic CO2 fixation to leaf nitrogen content (defined as instantaneous nitrogen-use efficiency, NUE) for the Himalayan forbs that were examined in situ were similar to the NUE values reported for lowland herbaceous species examined under lowland conditions. In contrast to the common belief, theoretical calculations indicate that the decrease in the rate of photosynthesis due to low atmospheric pressure is small. These Himalayan forbs appeared to overcome this small disadvantage by increasing stomatal conductance. Suppression of photosynthesis caused by blockage of stomata by raindrops appeared to be avoided by either of two mechanisms: plants had large hypostomatous leaves that expanded horizontally or they had obliquely oriented amphistomatous leaves without bundle sheath extensions. All these observations indicate that the gas-exchange characteristics of alpine forbs in the Eastern Himalaya are adapted to the local wet and humid monsoon conditions and thus photosynthetic rates attained during the monsoon period are similar to those of lowland plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00323490
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 71
    Electronic Resource
    Electronic Resource
    Photosynthetic and structural acclimation to light direction in vertical leaves of Silphium terebinthinaceum (1993)
    Springer
    Oecologia 95 (1993), S. 393-400 
    Details
    ISSN: 1432-1939
    Keywords: Functional symmetry ; Leaf anatomy ; Leaf orientation ; Light environment ; Photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The azimuth of vertical leaves of Silphium terebinthinaceum profoundly influenced total daily irradiance as well as the proportion of direct versus diffuse light incident on the adaxial and abaxial leaf surface. These differences caused structural and physiological adjustments in leaves that affected photosynthetic performance. Leaves with the adaxial surface facing East received equal daily integrated irradiance on each surface, and these leaves had similar photosynthetic rates when irradiated on either the adaxial or abaxial surface. The adaxial surface of East-facing leaves was also the only surface to receive more direct than diffuse irradiance and this was the only leaf side which had a clearly defined columnar palisade layer. A potential cost of constructing East-facing leaves with symmetrical photosynthetic capcity was a 25% higher specific leaf mass and increased leaf thickness in comparison to asymmetrical South-facing leaves. The adaxial surface of South-facing leaves received approximately three times more daily integrated irradiance than the abaxial surface. When measured at saturating CO2 and irradiance, these leaves had 42% higher photosynthetic rates when irradiated on the adaxial surface than when irradiated on the abaxial surface. However, there was no difference in photosynthesis for these leaves when irradiated on either surface when measurements were made at ambient CO2. Stomatal distribution (mean adaxial/abaxial stomatal density = 0.61) was unaffected by leaf orientation. Thus, the potential for high photosynthetic rates of adaxial palisade cells in South-facing leaves at ambient CO2 concentrations may have been constrained by stomatal limitations to gas exchange. The distribution of soluble protein and chlorophyll within leaves suggests that palisade and spongy mesophyll cells acclimated to their local light environment. The protein/chlorophyll ratio was high in the palisade layers and decreased in the spongy mesophyll cells, presumably corresponding to the attentuation of light as it penetrates leaves. Unlike some species, the chlorophyll a/b ratio and the degree of thylakoid stacking was uniform throughout the thickness of the leaf. It appears that sun-shade acclimation among cell layers of Silphium terebinthinaceum leaves is accomplished without adjustment to the chlorophyll a/b ratio or to thylakoid membrane structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00320994
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 72
    Electronic Resource
    Electronic Resource
    Importance of the gradient in photosynthetically active radiation in a vegetation stand for leaf nitrogen allocation in two monocotyledons (1993)
    Springer
    Oecologia 95 (1993), S. 416-424 
    Details
    ISSN: 1432-1939
    Keywords: Brachypodium pinnatum ; Carex acutiformis ; Nitrogen allocation ; Photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Carex acutiformis and Brachypodium pinnatum were grown with a uniform distribution of photosynthetic photon flux density (PFD) with height, and in a vertical PFD gradient similar to the PFD gradient in a leaf canopy. Distribution of organic leaf N and light-saturated rates of photosynthesis were determined. These parameters were also determined on plants growing in a natural vegetation stand. The effect of a PFD gradient was compared with the effect of a leaf canopy. In Brachypodium, plants growing in a vegetation stand had increasing leaf N with plant height. However, distribution of leaf N was not influenced by the PFD gradient treatment. The gradient of leaf N in plants growing in a leaf canopy was not due to differences within the long, mostly erect, leaves but to differences between leaves. In Carex, however, the PFD gradient caused a clear increase of leaf N with height in individual leaves and thus also in plants. The leaf N gradient was similar to that of plants growing in a leaf canopy. Leaf N distribution was not affected by nutrient availability in Carex. In most cases, photosynthesis was positively related to leaf N. Hence, lightsaturated rates of photosynthesis increased towards the top of the plants growing in leaf canopies in both species and, in Carex, also in the PFD gradient, thus contributing to increased N use efficiency for photosynthesis of the whole plant. It is concluded that in Carex the PFD gradient is the main environmental signal for leaf N allocation in response to shading in a leaf canopy, but one or more other signals must be involved in Brachypodium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00320997
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 73
    Electronic Resource
    Electronic Resource
    Increased photosynthesis and water potentials in Silphium integrifolium galled by cynipid wasps (1993)
    Springer
    Oecologia 93 (1993), S. 114-120 
    Details
    ISSN: 1432-1939
    Keywords: Photosynthesis ; Water potential ; Gall insect ; Silphium integrifolium ; Plant-insect interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Interactions between drought, insect herbivory, photosynthesis, and water potential play a key role in determining how plants tolerate and defend against herbivory, yet the effects of insect herbivores on photosynthesis and water potential are seldom assessed. We present evidence that cynipid wasp galls formed by Antistrophus silphii on Silphium integrifolium increase photosynthesis (A), stomatal conductance (g), and xylem water potential (Ψ). Preliminary data showed that in drought-stressed plants galled shoots had 36% greater A, and 10% greater stem Ψ than ungalled shoots, while in well-watered plants leaf gas exchange was not affected by galls. We hypothesized that 1) galled shoots have higher Ψ, g, and A than ungalled shoots, but this differences diminishes if plant drought stress is reduced, and 2) galls can reduce decreases in A and g if water availability decreases. A field experiment testing the first hypothesis found that galls increased g and Ψ, but that differences between galled and ungalled shoots did not diminish after plants were heavily watered. A laboratory test of the second hypothesis using potted Silphium found that galled plants had smaller drops in A and g over a 4-day dry-down period. A vs g and A vs intercellular CO2 concentration relationships were consistent with the explanation that increased Ψ allows galls to increase A by reducing stomatal limitation of A, rather than by altering sink-source relationships or by removing low-Ψ limitations on non-stomatal components of A. Our working hypothesis is that galls increase Ψ and A by reducing the shoot: root ratio so that the plant is exploiting a greater soil volume per unit leaf area. We argue that increased A is an ineffective way for Silphium to compensate for negative effects of gall insect attack. Instead, increased Ψ and A may protect gall insects from variation in resource availability caused by periodic drought stress, potentially reducing negative effects of drought on plant quality and on gall insect populations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00321200
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 74
    Electronic Resource
    Electronic Resource
    Photosynthetic induction times in shade-tolerant species with long and short-lived leaves (1993)
    Springer
    Oecologia 93 (1993), S. 165-170 
    Details
    ISSN: 1432-1939
    Keywords: Photosynthesis ; Induction ; Light flecks ; Leaf lifespan ; Rainforest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In the understory of a tropical rainforest, light flecks can contribute 10–80% of the total light flux. We investigated the capacity of eight shade-tolerant species to use light flecks by examining the time required for full induction of photosynthesis during an artificial light fleck. CO2 fixation rates were measured with a portable LiCor gas-exchange system for plants growing in the field on Barro Colorado Island, Panama. In all species induction to 50% of maximum CO2 fixation occurred quickly, from 1 to 3 min. In species with short leaf lifetimes (1 year), induction to 90% of maximum also occurred quickly, in 3–6 min. In contrast, the species with longer lived leaves (〉4 years) required 11–36 min for induction to 90% of maximum. Induction times for leaves from gap and understory plants of the same species were indistinguishable. Elevated CO2 did not eliminate the slow induction phase of long-lived leaves. This suggests that slow induction did not result from stomatal limitation. O2 evolution, measured on excised leaf disks, induced in 3–4 min in species with short-lived leaves, and 4–8 min in species with long-lived leaves. The rapid induction of O2 evolution indicates that the slower induction of CO2 fixation in long-lived leaves was not caused by a delay in the induction of electron transport. Activation of rubisco may be the major factor limiting response times in species with long-lived leaves. Species from Panama with short-lived leaves had remarkably rapid induction times that are comparable to those of algae or higher plant chloroplasts. We also found that understory forest plants induced two to seven times more quickly than did potted plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00317666
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 75
    Electronic Resource
    Electronic Resource
    Morning vs afternoon sun patches in experimental forest gaps: consequences of temporal incongruency of resources to birch regeneration (1993)
    Springer
    Oecologia 94 (1993), S. 235-243 
    Details
    ISSN: 1432-1939
    Keywords: Betula ; Photosynthesis ; Seedling regeneration ; Timing of resource availability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We investigated whether the timing of high light availability as sun patches within forest gaps, independent of total or peak photosynthetic photon flux (PPF), influences the physiology and growth of four coexisting birch species (Betula alleghaniensis, B. lenta, B. papyrifera, and B. populifolia). Birch seedlings were grown for two years along either the east or west sides of experimental gap structures and at two moisture levels. Seedlings positioned in the west received sun patches earlier in the day than those in the east, and environmental conditions for carbon gain were generally more favorable during the earlier sunpatches in the west; air and leaf temperatures were lower, and relative humidity higher, relative to conditions during sun patches in the cats, simulating patterns observed in natural forest gaps. Seedlings positioned along the west edges of gaps fixed more carbon earlier in the day than those in the east, and in many cases, peak net photosynthetic rates were greater for west positioned seedlings. In year two, leaf-level integrated daily carbon gain was greater for west- than eastpositioned plants, and for the most pioneer species, B. populifolia, differences between west and east seedlings were greatest at lower soil moisture levels. Despite some small effects on leaf gas exchange, the timing of high light availability, and its temporal congruence with other factors critical to carbon gain, had no significant effects on first or second year seedling biomass. The responses of birch seedlings to controlled variations in the timing of high light availability were generally much smaller than birch seedling responses to variations in other components of daily light regimes such as total integrated and peak PPF.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00341322
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 76
    Electronic Resource
    Electronic Resource
    Early-spring gas exchange and uptake of deuterium-labelled water in the poikilohydric fernPolypodium virginianum (1993)
    Springer
    Oecologia 95 (1993), S. 9-13 
    Details
    ISSN: 1432-1939
    Keywords: Fern physiology ; Deuterium ; Water uptake ; Photosynthesis ; Leaf conductance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This study was carried out to determine if the desiccation-tolerant fernPolypodium virgimanum L. ecologically resembles lower plants by absorbing atmospheric water through its fronds and actively growing in early spring when the soil along cliff edges is still frozen. Three times between February and April, 1991,P. virginianum clonal mats were treated with deuterium-labelled water. Following each application, fronds were collected over several days and analyzed for the presence of deuterium. Two treatment groups plus a control were used: fronds were sprayed directly while covering the soil, or the roots were watered while protecting the fronds. The control mats were left untreated. Soil, air, and frond temperatures, plus photosynthesis and frond conductance were monitored throughout the study period. At subfreezing temperatures in February, no labelled water was taken up from the soil and no photosynthesis took place. Small amounts of label were absorbed from the soil in March during freeze-thaw cycles when rates of photosynthesis and stomatal conductance were both low. Large amounts of label were taken up from the soil in April when the soil was fully thawed and gas exchange was at normal seasonal levels. Label was not absorbed directly through the fronds when the plants were actively growing. Despite the desiccation tolerance ofP. virginianum, the timing and patterns of its water uptake and gas exchange in early spring resemble those found in higher vascular plants, not poikilohydric lower plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00649500
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 77
    Electronic Resource
    Electronic Resource
    Characterization of a restriction barrier and electrotransformation of the cyanobacterium Nostoc PCC 7121 (1993)
    Springer
    Archives of microbiology 160 (1993), S. 229-237 
    Details
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Nostoc sp. PCC 7121 ; Heterotrophy ; N2-fixation ; Photosynthesis ; Cytochrome b6-f complex ; Restriction ; Modification ; Electroporation ; Transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have investigated host restriction as a barrier to transformation and developed a method for gene transfer into the previously untransformable, heterotrophic cyanobacterium Nostoc PCC 7121. A restriction endonuclease, designated Nsp 7121I, has been partially purified by phosphocellulose chromatography of Nostoc cell extract. Comparisons of Nsp 7121I digests of bacteriophage lambda and plasmid DNAs with computer-generated restriction fragment profiles showed that Nsp 7121I is an isoschizomer of restriction endonucleases, such as Asu I, Nsp 7524IV, Sau 96I, and Eco 47II, that recognize the sequence GGNCC. Cleavage by Nsp 7121I within this sequence was confirmed by sequence analysis of DNA fragments cleaved at a unique Nsp 7121I site. These data further suggested that cleavage occurs after the first G (5′-G/GNCC-3′) in this site to generate a three base 5′ overhang. Nsp 7121I degraded all plasmids used in previous transformation attempts but modification of these DNA molecules by Eco 47II methylase effectively prevented digestion by Nsp 7121I. Plasmids premethylated by passage through Escherichia coli carrying a plasmid encoded Eco 47II methylase have now been used in an electroporation procedure to transform Nostoc PCC 7121 to neomycin resistance at frequencies as high as one transformant per 103 viable cells. Transformation, and stable replication within Nostoc of one of the transforming plasmids (pRL25), was confirmed by recovery of pRL25, in its original form, from transformants. Conjugal transfer of pRL25 from E. coli into Nostoc was also possible but at much lower efficiency than by electroporation. These findings establish the basis for genetic analysis of Nostoc PCC 7121, from which genes for photosynthetic electron transport have been cloned.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00249129
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 78
    Electronic Resource
    Electronic Resource
    Rhodospirillum sodomense, sp. nov., a Dead Sea rhodospirillum species (1993)
    Springer
    Archives of microbiology 160 (1993), S. 363-371 
    Details
    ISSN: 1432-072X
    Keywords: Anoxygenic phototrophic bacteria ; Purple bacteria ; Rhodospirillum sodomense ; Dead Sea ; Hypersaline environments ; Photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new species of halophilic anoxygenic purple bacteria of the genus Rhodospirillum is described. The new organism, isolated from water/sediment of the Dead Sea, was vibrio-shaped and an obligate halophile. Growth was best at 12% NaCl, with only weak growth occurring at 6% or 21% NaCl. Growth occurred at Mg2+ concentrations up to 1 M but optimal growth was obtained at 0.05–0.1 M Mg2+. Bromide was well tolerated as an alternative anion to chloride. The new organism is an obligate phototroph, growing photoheterotrophically in media containing yeast extract and acetate or a few other organic compounds. Growth of the Dead Sea Rhodospirillum species under optimal culture conditions was slow (minimum td ∼ 20 h). Cells contained bacteriochlorophyll a and carotenoids of the spirilloxanthin series and mass cultures were pink in color. Absorption spectra revealed the presence of a B875 (light-harvesting I) but no B800/B850 (light-harvesting II) photopigment complex. The new organism shares a number of properties with the previously described halophilic phototrophic bacterium Rhodospirillum salinarum and was shown to be related to this phototroph by 16S rRNA sequencing. However, because of its salinity requirements, photosynthetic properties, and isolation from the Dead Sea, the new phototroph is proposed as a new species of the genus Rhodospirillum, R. sodomense.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00252222
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 79
    Electronic Resource
    Electronic Resource
    Upper temperature limits for growth and diazotrophy in the thermophilic cyanobacterium HTF Chlorogloeopsis (1993)
    Springer
    Archives of microbiology 159 (1993), S. 423-427 
    Details
    ISSN: 1432-072X
    Keywords: Chlorogloeopsis ; Continuous culture ; Cyanobacterium ; Nitrogen fixation ; Oxygen effects ; Photosynthesis ; Respiration ; Temperature effects ; Thermophile
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of temperature and oxygen on diazotrophic growth of the thermophilic cyanobacterium HTF (High Temperature Form) Chlorogloeopsis was investigated using cells grown in light-limited continuous culture at a dilution rate of 0.02 h-1. Diazotrophy was more sensitive to elevated temperatures than growth with combined nitrogen. The maximum temperature for growth of cultures gassed with CO2-enriched air was more than 55 °C but less than 60 °C with N2 as the sole nitrogen source, but between 60°C and 65°C when nitrate was present in the medium. The effect of temperature on nitrogenase activity, photosynthesis and respiration in the dark was determined using cells grown at 55°C. Maximal rates of all three processes were observed at 55°C and rates at 60°C during shortterm incubations were not less than 75% of the maximum. However, nitrogenase activity at 60°C was unstable and decayed at a rate of 2.2 h-1 under air and at 0.3 h-1 under argon. Photosynthesis and respiration were more stable at 60°C than anoxic nitrogen fixation. The upper temperature limits for diazotrophic growth thus seem to be set by the stability of nitrogenase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00288588
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 80
    Electronic Resource
    Electronic Resource
    Photosynthetic responses in developing and year-old Douglas-fir needles during new shoot development (1993)
    Springer
    Trees 8 (1993), S. 61-66 
    Details
    ISSN: 1432-2285
    Keywords: Douglas-fir ; Rubisco ; Translocation of nutrients ; Chlorophyll a fluorescence ; Photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A transient decline in photosynthetic rate and several correlates of photosynthetic function in year-old shade needles coincided with shoot elongation in 15 fullsib 8-year-old Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] saplings. In year-old needles and current year needles collected from May to November from branchlets with a single terminal bud and at least 4 needle age classes, chlorophyll (chl) content, photosynthetic rate and non-photochemical quenching of chl fluorescence declined during the period of flushing of the new shoots and recovered as shoot elongation slowed. Developing shade needles did not achieve the same oxygen evolution rate per unit area as the year-old needles, but did develop a higher quantum yield (estimated from chl a fluorescence). In short, in shade branchlets shoot development occurred at a cost of photosynthetic function in year-old needles. In year-old sun needles collected from the upper portions of the same trees, total protein concentration increased prior to, and decreased during, flushing. The concentration of ribulose 1,5-bisphosphate carboxylase-oxygenase (Rubisco) rose and decreased more than chlorophyll-binding proteins. In general, protein concentration in needles reflected age class rather than sun or shade environment. A specific decline in Rubisco in year-old sun needles during the period of new shoot elongation strengthens the hypothesis that degradation of this photosynthetic protein contributes to development of the new shoot.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00240983
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 81
    Electronic Resource
    Electronic Resource
    Leaf gas exchange of beech (Fagus sylvatica L.) seedlings in lightflecks: effects of fleck length and leaf temperature in leaves grown in deep and partial shade (1993)
    Springer
    Trees 7 (1993), S. 160-168 
    Details
    ISSN: 1432-2285
    Keywords: Photosynthesis ; Lightflecks ; Photosynthetic induction ; Leaf temperature ; Sun and shade leaves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Responses of leaf gas exchange in shade and half-shade grown seedlings of the European beech, Fagus sylvatica L., to constant light conditions indicate different phases of photosynthetic induction: an immediate, a fast and a subsequent slow phase. The slow phase has both biochemical and stomatal components. The higher the induction, the higher the lightfleck utilization efficiency (LUE) attributable to a lightfleck. LUE can be higher than 100% compared to a theoretical instantaneous response. Lightfleck quantum yield (total carbon gain attributable to a lightfleck per incident quantum density in the fleck) is highest in short pulses of light. Post-illumination carbon gain initially increases with fleck length, levelling off above 20 s. The lower the induction, the longer carbon is fixed post-illuminatively (up to 84 s) but the less carbon is gained. Shade leaves are induced much faster than partial shade leaves. They utilize series of lightflecks to become fully induced, while half-shade (and sun) leaves depend on continuous high light. Half-shade leaves lose induction faster in low light between lightflecks. High as well as low temperatures strongly delay induction in half-shade but not in shade leaves. In general, shade leaves are much better adapted to the dynamic light environment of the forest understorey; however, their water-use efficiency during induction is lower.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00199617
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 82
    Electronic Resource
    Electronic Resource
    Photosynthetic performance and nutrient status of Norway spruce [Picea abies (L.) Karst.] at forest sites in the Ore Mountains (Erzgebirge) (1993)
    Springer
    Trees 7 (1993), S. 115-122 
    Details
    ISSN: 1432-2285
    Keywords: Air pollution ; Forest decline ; Photosynthesis ; Picea abies ; Sulfur dioxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Photosynthetic performance of several needle age classes of Norway spruce trees [Picea abies (L.) Karst.] in highly SO2-polluted and heavily damaged forest sites was measured at two different locations in the Ore Mountains (Erzgebirge, Krusne Hory) during early summer. The carboxylation efficiency showed a dramatic drop from current-year's needles to 1-year-old needles with only a slight further decrease with increased needle age. The light use efficiency also revealed these characteristics. For both parameters, no linear decrease with needle age could be found. In contrast, the maximum photosynthetic capacity (A2500) decreased linearly with time and revealed a good correlation with the total sulfur content of the needles. Absolute values measured for A2500 were approximately 50% lower than those of comparable trees in the nearby Fichtelgebirge. Mineral deficiencies or acute nutrient imbalances of the needles were not detected. In contrast to the situation in the forests of the Fichtelgebirge, a direct effect of gaseous SO2 on the trees in the Ore Mountains seems plausible.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225478
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 83
    Electronic Resource
    Electronic Resource
    Modelling C3 photosynthesis: A sensitivity analysis of the photosynthetic carbon-reduction cycle (1993)
    Springer
    Planta 191 (1993), S. 421-432 
    Details
    ISSN: 1432-2048
    Keywords: Control coefficient ; Helianthus (photosyntesis) ; Model (C3 photosynthesis) ; Photosynthesis ; Sensitivity analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A model of the C 3 photosynthetic system is developed which describes the sensitivity of the steadystate rate of carbon dioxide assimilation to changes in the activity of several enzymes of the system. The model requires measurements of the steady-state rate of carbon dioxide assimilation, the concentrations of several intermediates in the photosynthetic system, and the concentration of the active site of ribulose 1,5-bisphosphate carboxyalse/oxygenase (Rubisco). It is shown that in sunflowers (Helianthus annuus L.) at photon flux densities that are largely saturating for the rate of photosynthesis, the steady-stete rate of carbon dioxide assimilation is most sensitive to Rubisco activity and, to a lesser degree, to the activities of the stromal fructose, 6-bisphosphatase and the enzymes catalysing sucrose synthesis. The activities of sedoheptulose 1,7-bisphosphatase, ribulose 5-phosphate kinase, ATP synthase and the ADP-glucose pyrophosphorylase are calculated to have a negligible effect on the flux under the high-light conditions. The utility of this analysis in developing simpler models of photosynthesis is also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00195743
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 84
    Electronic Resource
    Electronic Resource
    Quantum yields for uptake of carbon dioxide in C3 vascular plants of contrasting habitats and taxonomic groupings (1993)
    Springer
    Planta 189 (1993), S. 226-234 
    Details
    ISSN: 1432-2048
    Keywords: C3 plant ; Photosynthesis ; Quantum yield (O2, CO2 uptake)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The maximum quantum yields (ϕa,c) for CO2 uptake in low-oxygen atmospheres were determined for 11 species of C3 vascular plants of diverse taxa, habitat and life form using an Ulbricht-sphere leaf chamber. Comparisons were also made between tissues of varied age within species. The species examined were Psilotum nudum (L.) P. Beauv., Davallia bullata Wall. ex Hook., Cycas revoluta Thunb., Araucaria heterophylla (Salisb.) Franco, Picea abies (L.) Karst., Nerium oleander L., Ruellia humilis Nutt., Pilea microphylla (L.) Karst., Beaucarnea stricta Lem., Oplismenus hirtellus (L.) P. Beauv. and Poa annua L. Quantum yields were calculated from the initial slopes of the response of CO2 uptake to the quantity of photons absorbed in conditions of diffuse lighting. Regression analysis of variance of the initial slopes of the response of CO2 uptake to photon absorption failed to show any statistically significant differences between age classes within species or between the mature photosynthetic organs of different species. The constancy of ϕa,c was apparent despite marked variation in the light-saturated rates of CO2 uptake within and between species. The mean ϕa,c was 0.093±0.003 for 11 species. By contrast, surface absorptance varied markedly between species from 0.90 to 0.60, producing proportional variation in the quantum yield calculated on an incidentlight basis. The ratio of variable to maximum fluorescence emission at 695 nm for the same tissues also failed to show any statistically significant variation between species, with a mean of 0.838±0.008. Mean values of ϕa,c reported here for C3 species, in the absence of photorespiration, are higher than reported in previous surveys of vascular plants, but consistent with recent estimates of the quantum yields of O2 evolution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00195081
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 85
    Electronic Resource
    Electronic Resource
    Evidence for two different blue-light-receptor systems for the fast responses of stimulation of photosynthetic capacity and acidification of the plant surface in brown algae (1993)
    Springer
    Planta 191 (1993), S. 489-495 
    Details
    ISSN: 1432-2048
    Keywords: Action spectroscopy ; Blue light (sensitivity) ; Flavin inhibitor ; Phaeophyta ; Photosynthesis ; pH shift
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two blue-light responses of Phaeophyta that are expressed within a few seconds of a blue-light stimulus were characterized with respect to their photoreception properties. The first response is the activation of red-light-saturated photosynthesis which can be stimulated to values up to 5 times the rates in red light, depending on the species. The second response is a blue-light-induced acidification measurable at the plant surface. Both responses have similar kinetic characteristics and thus led us initially to hypothesise that they were causally connected in the same transduction mechanism. The two responses have action spectra [measured for Ectocarpus siliculosus (Dillwyn) Lyngb. and Laminaria saccharina (L.) Lamouroux] that are indistinguishable within the relatively large limits of error. However, in all species tested, the threshold sensitivity for blue light of the photosynthetic response is lower than that of the pH-shift by a factor of 2 to 150. Furthermore, stimulation of photosynthesis is sensitive to the flavin inhibitors, KI and phenylacetic acid, but the pH response is not affected by these inhibitors. Thus, the blue-light-induced pH-shift does not cause the stimulation of photosynthesis. In contrast, the different fluence-response relationships of the two responses and particularly the differential effect of the inhibitors are clear evidence for the action of two independent transduction pathways and photoreceptor systems for blue light. At least photoreception for stimulation of photosynthesis involves a flavin-or and a pterin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00195750
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 86
    Electronic Resource
    Electronic Resource
    Contrasting crop species responses to CO2 and temperature: rice, soybean and citrus (1993)
    Springer
    Plant ecology 104-105 (1993), S. 239-260 
    Details
    ISSN: 1573-5052
    Keywords: Growth ; Yield ; Photosynthesis ; Water use ; Respiration ; Acclimation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The continuing increase in atmospheric carbon dioxide concentration ([CO2]) and projections of possible future increases in global air temperatures have stimulated interest in the effects of these climate variables on plants and, in particular, on agriculturally important food crops. Mounting evidence from many different experiments suggests that the magnitude and even direction of crop responses to [CO2] and temperature is almost certain to be species dependent and very likely, within a species, to be cultivar dependent. Over the last decade, [CO2] and temperature experiments have been conducted on several crop species in the outdoor, naturally-sunlit, environmentally controlled, plant growth chambers by USDA-ARS and the University of Florida, at Gainesville, Florida, USA. The objectives for this paper are to summarize some of the major findings of these experiments and further to compare and contrast species responses to [CO2] and temperature for three diverse crop species: rice (Oryza sativa, L.), soybean (Glycine max, L.) and citrus (various species). Citrus had the lowest growth and photosynthetic rates but under [CO2] enrichment displayed the greatest percentage increases over ambient [CO2] control treatments. In all three species the direct effect of [CO2] enrichment was always an increase in photosynthetic rate. In soybean, photosynthetic rate depended on current [CO2] regardless of the long-term [CO2] history of the crop. In rice, photosynthetic rate measured at a common [CO2], decreased with increasing long-term [CO2] growth treatment due to a corresponding decline in RuBP carboxylase content and activity. Rice specific respiration decreased from subambient to ambient and superambient [CO2] due to a decrease in plant tissue nitrogen content and a decline in specific maintenance respiration rate. In all three species, crop water use decreased with [CO2] enrichment but increased with increases in temperature. For both rice and soybean, [CO2] enrichment increased growth and grain yield. Rice grain yields declined by roughly 10 % per each 1 °C rise in day/night temperature above 28/21 °C.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00048156
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 87
    Electronic Resource
    Electronic Resource
    Effects of elevated CO2 on growth, photosynthesis and respiration of sweet chestnut (Castanea sativa Mill.) (1993)
    Springer
    Plant ecology 104-105 (1993), S. 413-419 
    Details
    ISSN: 1573-5052
    Keywords: Deciduous tree ; Dry matter distribution ; Photosynthesis ; Respiration ; Castanea sativa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two year old sweet chestnut seedlings (Castanea sativa Mill) were grown in pots at ambient (350 µmol·mol−1) and double (700 µmol·mol−1) atmospheric CO2 concentration in constantly ventilated greenhouses during entire growing seasons. CO2 enrichment caused either no significant change or a decrease in shoot response, depending on yearly weather conditions. Similarly, leaf area was either reduced or unchanged under elevated CO2. However, when grown under controlled conditions in a growth chamber, leaf area was enlarged with elevated CO2. The CO2 exchanges of whole plants were measured during the growing season. In elevated CO2, net photosynthetic rate was maximum in May and then decreased, reaching the level of the control at the end of the season. End of night dark respiration of enriched plants was significantly lower than that of control plants; this difference decreased with time and became negligible in the fall. The original CO2 level acted instantaneously on the respiration rate: a double concentration in CO2 decreased the respiration of control plants and a reduced concentration enhanced the respiration of enriched plants. The carbon balance of a chestnut seedling may then be modified in elevated CO2 by increased carbon inputs and decreased carbon outputs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00048170
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 88
    Electronic Resource
    Electronic Resource
    Assimilation, respiration and allocation of carbon inPlantago major as affected by atmospheric CO2 levels (1993)
    Springer
    Plant ecology 104-105 (1993), S. 369-378 
    Details
    ISSN: 1573-5052
    Keywords: CO2-Enrichment ; Relative growth rate ; Dry matter allocation ; Photosynthesis ; Respiration ; Carbon balance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The response ofPlantago major ssp,pleiosperma plants, grown on nutrient solution in a climate chamber, to a doubling of the ambient atmospheric CO2 concentration was investigated. Total dry matter production was increased by 30% after 3 weeks of exposure, due to a transient stimulation of the relative growth rate (RGR) during the first 10 days. Thereafter RGR returned to the level of control plants. Photosynthesis, expressed per unit leaf area, was stimulated during the first two weeks of the experiment, thereafter it dropped and nearly reached the level of the control plants. Root respiration was not affected by increased atmospheric CO2 levels, whereas shoot, dark respiration was stimulated throughout the experimental period. Dry matter allocation over leaves stems and roots was not affected by the CO2 level. SLA was reduced by 10%, which can partly be explained by an increased dry matter content of the leaves. Both in the early and later stages of the experiment, shoot respiration accounted for a larger part of the carbon budget in plants grown at elevated atmospheric CO2. Shifts in the total carbon budget were mainly due to the effects on shoot respiration. Leaf growth accounted for nearly 50% of the C budget at all stages of the experiment and in both treatments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00048166
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 89
    Electronic Resource
    Electronic Resource
    Open top chambers for exposing plant canopies to elevated CO2 concentration and for measuring net gas exchange (1993)
    Springer
    Plant ecology 104-105 (1993), S. 3-15 
    Details
    ISSN: 1573-5052
    Keywords: Open top chamber ; Gas exchange ; Photosynthesis ; Elevated CO2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Open top chamber design and function are reviewed. All of the chambers described maintain CO2 concentrations measured at a central location within ±30 ppm of a desired target when averaged over the growing season, but the spatial and temporal range within any chamber may be closer to 100 ppm. Compared with unchambered companion plots, open top chambers modify the microenvironment in the following ways: temperatures are increased up to 3°C depending on the chamber design and location of the measurement; light intensity is typically diminished by as much as 20%; wind velocity is lower and constant; and relative humidity is higher. The chamber environment may significantly alter plant growth when compared with unchambered controls, but the chamber effect on growth has not been clearly attributed to a single or even a few environmental factors. A method for modifying an open top chamber for tracking gas exchange between natural vegetation and the ambient air is described. This modification consists of the addition of a top with exit chimney to reduce dilution of chamber CO2 by external ambient air, is quickly made and permits estimation of the effects of elevated CO2 and water vapor exchange. The relatively simple design and construction of open top chambers make them the most likely method to be used in the near future for long-term elevated CO2 exposure of small trees, crops and grassland ecosystems. Improvements in the basic geometry to improve control of temperature, reduce the variation of CO2 concentrations, and increase the turbulence and wind speed in the canopy boundary layer are desirable objectives. Similarly, modifications for measuring water vapor and carbon dioxide gas exchange will extend the usefulness of open top chambers to include non-destructive monitoring of the responses of ecosystems to rising atmospheric CO2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00048141
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 90
    Electronic Resource
    Electronic Resource
    The atypical chlorophyll a/b/c light-harvesting complex of Mantoniella squamata: molecular cloning and sequence analysis (1993)
    Springer
    Molecular genetics and genomics 240 (1993), S. 403-413 
    Details
    ISSN: 1617-4623
    Keywords: Chlorophyta ; Lhc genes ; Light harvesting ; Mantoniella squamata ; Photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract cDNA species encoding precursor polypeptides of the chlorophyll a/b/c light-harvesting complex (LHC) of Mantoniella squamata were cloned and sequenced. The precursor polypeptides have molecular weights of 24.2 kDa and are related to the major chlorophyll a/b polypeptides of higher plants. Southern analysis showed that their genes belong to the nuclear encoded Lhc multigene family; the investigated genes most probably do not contain introns. The chlorophyll a/b/c polypeptides contain two highly conserved regions common to all LHC polypeptides and three hydrophobic α-helices, which span the thylakoid membrane. The first membrane-spanning helix, however, is not detected by predictive methods: its atypical hydrophilic domains may bind the chlorophyll c molecules within the hydrophobic membrane environment. Homology to LHC 11 of higher plants and green algae is specifically evident in the C-terminal region comprising helix III and the preceding stroma-exposed domain. The N-terminal region of 29 amino acids resembles the structure of a transit sequence, which shows only minor similarities to those of LHC II sequences. Strikingly, the mature light-harvesting polypeptides of M. squamata lack an N-terminal domain of 30 amino acids, which, in higher plants, contains the phosphorylation site of LHC 11 and simultaneously mediates membrane stacking. Therefore, the chlorophyll a/b/c polypeptides of M. squamata do not exhibit any light-dependent preference for photosystem I or 11. The lack of this domain also indicates that the attractive forces between stacked thylakoids are weak.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00280392
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 91
    Electronic Resource
    Electronic Resource
    Leaf gas exchange characteristics, daily carbon and water balances of the host/mistletoe pair Eucalyptus behriana F. Muell. and Amyema miquelii (Lehm. ex Miq.) Tiegh. at permanently low plant water status in the field (1992)
    Springer
    Trees 7 (1992), S. 1-7 
    Details
    ISSN: 1432-2285
    Keywords: Amyema miquelii ; Daily carbon balance ; Daily water balance ; Eucalyptus behriana ; Photosynthesis ; Water-use efficiency ; Xylem pressure ; Heterotrophy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Leaf gas exchange and xylem pressures of the xylem-tapping mistletoe, Amyema miquelii (Lehm. ex Miq.) Tiegh., and its host, Eucalyptus behriana F. Muell., both growing under permanently low plant water status, are studied under controlled and naturally fluctuating field conditions. Stomata of both plants regulate transpiration with respect to light and air humidity, but leaf conductances and total daily transpiration are up to 7.3 times higher in the host. Despite this, water-use efficiency in the mistletoe is lower than in the host. In the light of the mistletoe's low transpiration rates observed in spring, a commonly accepted pattern of higher water losses from parasites is likely to be inconsistent over a season. The role of partial parasitic carbon heterotrophy is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225225
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 92
    Electronic Resource
    Electronic Resource
    The effects of water and multi-nutrient stress on xylem sap chemistry, photosynthesis and transpiration of seedlings of two Eucalypts (1992)
    Springer
    Trees 6 (1992), S. 7-12 
    Details
    ISSN: 1432-2285
    Keywords: Eucalyptus ; Nutrients ; Photosynthesis ; Transpiration ; Xylem sap
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Ten seedlings each of Eucalyptus kitsoniana Maiden and Eucalyptus globulus Labill. were subjected to two levels of water stress and two levels of nutrient stress (macro and micro-nutrients) in a greenhouse for 3 weeks. The objectives were to determine the degree to which seedlings show differences in sap chemistry, photosynthesis and transpiration that relate to the environments in which these two species live. Whole plants were then extracted for xylem sap using a pressure chamber and the sap was analyzed for 14 elements using an inductively coupled plasma spectrometer and a nitrometer. For E. kitsoniana water and nutrient stress, applied separately or in combination, significantly reduced leaf conductance, transpiration, photosynthesis and midday water potential. Nutrient stress alone had less effect than water stress on most functions measured. Water stress alone reduced the root/shoot ratio; the combination of water and nutrient stress increased the root/shoot ratio, primarily because of reduced shoot weight. In E. kitsoniana, water stress alone or in combination with nutrient stress increased the xylem sap concentrations of B and Si. Multi-nutrient stress alone, or in combination with water stress, significantly decreased sap Zn and K. For this species, sap N was decreased by nutrient stress, but increased by water stress. E. globulus had significantly lower transpiration rates and less root mass than E. kitsoniana. Slightly lower leaf conductance and photosynthesis were not significant in E. globulus compared to E. kitsoniana. Water and nutrient stress reduced conductance, transpiration (except for nutrient stress) and photosynthesis, and the effects of water stress on E. globulus were greater than the effects of nutrient stress. Midday water potential was reduced by water stress. Water or nutrient stress alone did not alter seedling root/shoot ratio, but the combination of water and nutrient stress significantly increased the root/shoot ratio for both species. For E. globulus, sap concentrations of Mn, Na, Si and K were increased by water stress (alone or in combination with nutrient stress). Sap N increased with water stress or combined stresses, but decreased under nutrient stress alone. When the two species were compared, E. globulus generally had lower or similar nutrient concentrations in the sap, with Ca, Mg, Mn and P significantly lower than in E. kitsoniana. Seedlings of these two species show strong site adaptations to water and nutrient availability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224492
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 93
    Electronic Resource
    Electronic Resource
    The influence of ozone on the stomatal and non-stomatal limitation of photosynthesis in Norway spruce, Picea abies (L.) Karst, exposed to soil moisture deficit (1992)
    Springer
    Trees 6 (1992), S. 128-136 
    Details
    ISSN: 1432-2285
    Keywords: Norway spruce ; Ozone ; Photosynthesis ; Stomatal limitation of photosynthesis ; Drought stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Norway spruce, Picea abies (L.) Karst., was exposed to charcoal-filtered air (CF) and non-filtered air + ozone (NF+) and periods of soil moisture deficit from 1985 to 1988 in open-top chambers. Net photosynthesis, stomatal conductance, needle water potential and various shoot properties were measured on 1-year-old shoots during a period of soil moisture deficit. The gas exchange was measured at saturating photosynthetic photon flux density and across a range of CO2 concentrations. The soil moisture deficit induced a mild drought stress in the plants, expressed by a pre-dawn needle water potential of approximately-0.9 MPa and a substantial reduction in net photosynthesis and gas phase conductance. In the CF treatment, intercellular CO2 concentration was reduced, but was unaffected in the NF+ treatment. Furthermore, net photosynthesis declined more in response to the soil moisture deficit in the NF+ treatment than in the CF treatment. This is suggested to be attributed to the carboxylation efficiency at the operating point, which was decreased by 47% and 64% in shoots from the CF and the NF+ treatments, respectively. Stomatal limitation of net photosynthesis was increased by drought by 24–45% in the CF treatment, while it was unaffected in the NF+ treatment. Thus, our results imply that the coupling between the stomatal conductance and the photosynthetic rate was changed and that the marginal cost of water per given amount of carbon gain will increase in trees exposed to ozone, during periods of drought.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00202428
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 94
    Electronic Resource
    Electronic Resource
    The influence of leaf area on the rooting physiology of leafy stem cuttings of Terminalia spinosa Engl. (1992)
    Springer
    Trees 6 (1992), S. 210-215 
    Details
    ISSN: 1432-2285
    Keywords: Vegetative propagation ; Percentage rooting ; Leaf area ; Photosynthesis ; Stomatal conductance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The effect of different leaf areas on the rooting of Terminalia spinosa Engl. cuttings in an non-mist propagation system in glasshouses at Edinburgh was investigated by trimming the leaves to 0, 7.5, 15 and 30 cm2 before cuttings were severed from stockplants. Cuttings were taken to a standard length of 5 cm from the lateral shoots of previously pruned stockplants grown in a tropicalised glasshouse. During the rooting period, photosynthetic rate, stomatal conductance, water potential and relative water content of the cuttings were assessed at regular intervals. It was found that (i) removal of the entire leaf area prevented rooting; (ii) cuttings with a 7.5 cm2, 15 cm2 and 30 cm2 leaf all achieved 80% rooting after 3 weeks; (iii) an increase in leaf area from 7.5 cm2 to 30 cm2 increased the rate of rooting and the length of the longest root after 2 weeks, but also increased the number of original leaves abscised after 6 weeks; and (iv) the greatest number of new leaves were produced by cuttings with 7.5 cm2 and 15 cm2 leaf area per cutting. All leafy cuttings actively photosynthesized during the propagation period, with a mean rate of 2 μmol CO2 m-2 s-1 with an irradiance of 100 μmol m-2 s-1. Cuttings with 30 cm2 leaf area had lower relative water contents, lower stomatal conductances and lower photosynthetic rates per unit leaf area than those with a 7.5 cm2 and 15 cm2 leaf. It was concluded that T. spinosa cuttings are easy to root, provided the cuttings have leaves to produce current assimilates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224338
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 95
    Electronic Resource
    Electronic Resource
    Role of carbonic anhydrase in photosynthesis and inorganic-carbon assimilation in the red alga Gracilaria tenuistipitata (1992)
    Springer
    Planta 187 (1992), S. 275-281 
    Details
    ISSN: 1432-2048
    Keywords: Carbon assimilation ; Carbonic anhydrase ; Carbon dioxide uptake ; Gracilaria ; Photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The mechanism of inorganic-carbon (Ci) accumulation in the red seaweed Gracilaria tenuistipitata Zhang et Xia has been investigated. Extracellular and intracellular carbonic-anhydrase (CA) activities have been detected. Photosynthetic O2 evolution in thalli and protoplasts of G. tenuistipitata were higher at pH 6.5 than at pH 8.6, where HCO 3 − is the predominant form of Ci. Dextran-bound sulfonamide (DBS), a specific inhibitor of extracellular CA, reduced photosynthetic O2 evolution at pH 8.6 and did not have any effect at pH 6.5. After inhibition with DBS, O2 evolution was similar to the rate that could be supported by CO2 from spontaneous dehydration of HCO 3 − . The rate of photosynthetic alkalization of the surrounding medium by the algal thallus was dependent on the concentration of Ci and inhibited by DBS. We suggest that the general form of Ci that enters through the plasma membrane of G. tenuistipitata is CO2. Bicarbonate is utilized mainly by an indirect mechanism after dehydration to CO2, and this mechanism involves extracellular CA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00201951
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 96
    Electronic Resource
    Electronic Resource
    Role of external carbonic anhydrase in light-dependent alkalization by Fucus serratus L. and Laminaria saccharina (L.) Lamour. (Phaeophyta) (1992)
    Springer
    Planta 188 (1992), S. 1-6 
    Details
    ISSN: 1432-2048
    Keywords: Alkalization ; Carbon assimilation ; Carbonic anhydrase ; Fucus ; Laminaria ; Macroalgae ; Photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract It has been proposed that many marine macroalgae are able to utilize HCO 3 − for photosynthesis and growth, and that energy-dependent ion pumping is involved in this process. We have therefore studied the light-dependent alkalization of the surrounding medium by two species of marine macroscopic brown algae, Fucus serratus L. and Laminaria saccharina (L.) Lamour. with the aim of investigating the role of extracellular carbonic anhydrase (EC 4.2.1.1.) in the assimilation of inorganic carbon from the seawater medium. In particular, the influence of membrane-impermeable or slowly permeable carbonic-anhydrase inhibitors on the rate of alkalization of the seawater has been investigated. Inhibition of the alkalization rate occurred in both species at an alkaline pH (pH 8.0) but no inhibition was observed at an acidic pH (pH 6.0). The alkalization was found to be light-dependent and inhibited by 3-(3′,4′-dichlorophenyl)-1, 1-dimethylurea and, thus, correlated with photosynthesis. Alkalization by macroalgae has previously been shown to be proportional to inorganiccarbon uptake. We suggest that alkalization of the medium at alkaline pH in both of the species examined is mainly the consequence of an extracellular reaction. The reaction is catalyzed by extracellular carbonic anhydrase which converts HCO 3 − to OH− and CO2; CO2 is then taken up through the plasmalemma. However, we do not exclude the involvement of other mechanisms of inorganic-carbon uptake.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00198932
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 97
    Electronic Resource
    Electronic Resource
    Role of external carbonic anhydrase in light-dependent alkalization byFucus serratus L. andLaminaria saccharina (L.) Lamour. (Phaeophyta) (1992)
    Springer
    Planta 188 (1992), S. 1-6 
    Details
    ISSN: 1432-2048
    Keywords: Alkalization ; Carbon assimilation ; Carbonic anhydrase ; Fucus ; Laminaria ; Macroalgae ; Photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract It has been proposed that many marine macroalgae are able to utilize HCO 3 − for photosynthesis and growth, and that energy-dependent ion pumping is involved in this process. We have therefore studied the light-dependent alkalization of the surrounding medium by two species of marine macroscopic brown algae,Fucus serratus L. andLaminaria saccharina (L.) Lamour. with the aim of investigating the role of extracellular carbonic anhydrase (EC 4.2.1.1.) in the assimilation of inorganic carbon from the seawater medium. In particular, the influence of membrane-impermeable or slowly permeable carbonic-anhydrase inhibitors on the rate of alkalization of the seawater has been investigated. Inhibition of the alkalization rate occurred in both species at an alkaline pH (pH 8.0) but no inhibition was observed at an acidic pH (pH 6.0). The alkalization was found to be light-dependent and inhibited by 3-(3′,4′-dichlorophenyl)-1, 1-dimethylurea and, thus, correlated with photosynthesis. Alkalization by macroalgae has previously been shown to be proportional to inorganiccarbon uptake. We suggest that alkalization of the medium at alkaline pH in both of the species examined is mainly the consequence of an extracellular reaction. The reaction is catalyzed by extracellular carbonic anhydrase which converts HCO 3 − to OH− and CO2; CO2 is then taken up through the plasmalemma. However, we do not exclude the involvement of other mechanisms of inorganic-carbon uptake.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01160705
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 98
    Electronic Resource
    Electronic Resource
    Circadian rhythm and fast responses to blue light of photosynthesis in Ectocarpus (Phaeophyta, Ectocarpales) (1992)
    Springer
    Planta 187 (1992), S. 53-59 
    Details
    ISSN: 1432-2048
    Keywords: Ectocarpus (Phaeophyta) ; Circadian rhythm (photosynthesis) ; Blue light (stimulation of photosynthesis) ; Phase shifting (blue light) ; Photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The photosynthetic oxygen production of Ectocarpus siliculosus (Dillwyn) Lyngb. under continuous high irradiances of red light displayed a circadian rhythm with maxima at about noon. Pulses of blue light induced rapid transient increases in the rate of photosynthesis. The increases started about 15 s after the beginning of blue light and reached their maxima after 3–4 min. This was followed by a gradual decrease. A second peak or shoulder about 20 min later indicated that at least two reactions were involved in the blue-light enhancement of photosynthesis. The magnitude of the response to blue light depended on the phase of the rhythm at which blue light was given. It was high when the red-light photosynthesis was at its troughs, and low at its peaks. Fluence-response curves indicated that the sensitivity to blue light at the peaks of the rhythm was identical to that at the troughs. In addition, blue light shifted the phase of the photosynthetic rhythm, where the essential trigger was the light-off signal. Red light had no specific influence on the circadian rhythm. After darkness, photosynthetic rates were different from those under steady-state conditions. Two different transient bursts in the rate of O2 evolution could be distinguished, an early non-rhythmical one that was probably caused by accumulation of inorganic carbon inside the cells, and a second later one that appeared at the peak activity phases of the ciradian rhythm or after blue light. Its origins are unclear.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00201623
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 99
    Electronic Resource
    Electronic Resource
    Mechanistic differences in photoinhibition of sun and shade plants (1992)
    Springer
    Planta 188 (1992), S. 422-431 
    Details
    ISSN: 1432-2048
    Keywords: Light acclimation ; Photosynthesis ; Photoinhibition ; Photosystem II repair cycle ; Pisum ; Tradescantia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Leaf discs of the shade plant Tradescantia albiflora Kunth grown at 50 μmol · m−2 · s−1, and the facultative sun/shade plant Pisum sativum L. grown at 50 or 300 μmol · m−2, s−1, were photoinhibited for 4 h in 1700 μmol photons m−2 · s−1 at 22° C. The effects of photoinhibition on the following parameters were studied: i) photosystem II (PSII) function; ii) amount of D1 protein in the PSII reaction centre; iii) dependence of photoinhibition and its recovery on chloroplast-encoded protein synthesis; and, iv) the sensitivity of photosynthesis to photoinhibition in the presence or absence of the carotenoid zeaxanthin. We show that: i) despite different sensitivities to photoinhibition, photoinhibition in all three plants occurred at the reaction centre of PSII; ii) there was no correlation between the extent of photoinhibition and the degradation of the D1 protein; iii) the susceptibility to photoinhibition by blockage of chloroplas-tencoded protein synthesis was much less in shade plants than in plants acclimated to higher light; and iv) inhibition of zeaxanthin formation increased the sensitivity to photoinhibition in pea, but not in the shade plant Tradescantia. We suggest that there are mechanistic differences in photoinhibition of sun and shade plants. In sun plants, an active repair cycle of PSII replaces photoinhibited reaction centres with photochemically active ones, thereby conferring partial protection against photoinhibition. However, in shade plants, this repair cycle is less important for protection against photoinhibition; instead, photoinhibited PSII reaction centres may confer, as they accumulate, increased protection of the remaining connected, functional PSII centres by controlled, nonphotochemical dissipation of excess excitation energy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00192810
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 100
    Electronic Resource
    Electronic Resource
    Leaf life spans in wild perennial herbaceous plants: a survey and attempts at a functional interpretation (1992)
    Springer
    Oecologia 89 (1992), S. 10-16 
    Details
    ISSN: 1432-1939
    Keywords: Altitude ; Longevity ; Nitrogen ; Photosynthesis ; Specific leaf area
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Leaf longevity in 29 herbaceous plant species of Central Europe was studied by inspecting tagged leaves at weekly intervals. About half of the species are elements of the lowland meadow flora, the other half comprises a representative sample of species from the highest sites where vascular plants grow in the Alps. Shaded and water-stressed sites were avoided. Overall mean leaf longevity did not differ significantly between sites and amounted to 71±5 days at low and 68±4 days at high altitude. Leaf life spans ranged (with no clear altitudinal trend) from 41 to 95 days. Low-altitude forbs and grasses produced several leaf cohorts during their growth period, while most alpine species produced only one. Correlations were found between leaf duration and percent nitrogen content and carbon-cost/carbon-gain ratios, but not with leaf dry mass per unit leaf area and photosynthetic capacity alone. As leaf life spans increase, more C tends to be invested per unit CO2 uptake and less N is invested per unit invested C. Thus, mass relationships rather than area relationships seem to be linked to leaf life span in these species, suggesting that leaf duration is associated with properties other than the efficiency of light utilization (e.g. mechanical strength, herbivory or pathogen resistance). It seems that the explanations of leaf duration that have been developed for evergreen/deciduous plants and for plants along steep light gradients do not apply to the variable life spans in leaves of perennial herbaceous plants of open habitats.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00319009
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...