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  • 1
    Electronic Resource
    Electronic Resource
    Different regulation of leaf respiration between Spinacia oleracea, a sun species, and Alocasia odora, a shade species (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 101 (1997), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Mature leaves of shade species exhibit lower respiratory rates than those of sun species. To elucidate the mechanism underlying different respiratory rates between sun and shade species, we examined respiratory properties of leaves in Spinacia oleracea L., a sun species, and Alocasia odora (Lodd.) Spach, a shade species, with special reference to changes in the respiratory rate throughout the night. In S. oleracea, rates of both CO2 efflux and O2 uptake decreased with time during the night, whereas in A. odora both rates were virtually constant at lower levels. The rates of O2 uptake in S. oleracea increased upon addition of sucrose, and the rates attained were virtually identical throughout the night. However, the addition of an uncoupler [carbonyl cyanide p-(trifluoromethoxy)-phenylhydrazone; FCCP] did not alter the rates. In contrast, the rates of O2 uptake in A. odora were enhanced by the addition of FCCP, but not by sucrose. The concentrations of carbohydrates in the tissue decreased throughout the night in both species and the ATP/ADP ratio was always greater in A. odora. These results indicate that, in S. oleracea, the availability of respiratory substrate determines the respiratory rate, while the low respiratory rate in A. odora is ascribed to its low demand for ATP.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1997.tb01812.x
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  • 2
    Electronic Resource
    Electronic Resource
    The cause of PSI photoinhibition at low temperatures in leaves of Cucumis sativus, a chilling-sensitive plant (1998)
    Copenhagen : Munksgaard International Publishers
    Physiologia plantarum 103 (1998), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: In a chilling-sensitive plant, cucumber, chilling of leaves in the light results in irreversible damage to PSI. Recent in vitro studies suggested that hydroxyl radicals, which are formed in the presence of H2O2 and reduced Fe-S centers, are involved in the PSI inhibition. We therefore examined this possibility in vivo. Chilling of leaves at 5°C in the light caused a temporary increase in H2O2 concentration, which was probably due to the net H2O2 production in vivo. The activity, measured at 5°C, of the thylakoid ascorbate peroxidase (APX), a key enzyme of the H2O2-scavenging system, was about 20% of that measured at 25°C. The isolated thylakoids retaining high thylakoid APX activity did not show light-dependent net H2O2 production at 25°C. However, at 5°C, net production of H2O2 was observed. Since the rate of electron flow to molecular oxygen in the isolated thylakoids was ca 5 mmol e− mol−1 Chl s−1 at 5°C, the H2O2-scavenging capacity was below this level. When intact leaves were illuminated at 5°C at an irradiance of 100 µmol m−2 s−1, the rate of electron transport through PSII was ca 20 mmol e− mol−1 Chl s−1 and more than 80% of QA was in the reduced state. Since thylakoids are uncoupled in cucumber leaves at 5°C in the light. ATP is not formed and energy dissipation in the form of heat is suppressed. Therefore, the electron flow to molecular oxygen would be greater than 5 mmol e− mol−1 Chl s−1. Moreover, under such conditions, components in the electron transport chain, including Fe-S centers in PSI, were probably reduced. These features indicate that, when cucumber leaves are chilled in the light, hydroxyl radicals can be produced by the Fenton reaction and cause damage to PSI.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1399-3054.1998.1030301.x
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  • 3
    Electronic Resource
    Electronic Resource
    Temperature acclimation of photosynthesis in spinach leaves: analyses of photosynthetic components and temperature dependencies of photosynthetic partial reactions (2005)
    Oxford, UK : Blackwell Science Ltd
    Plant, cell & environment 28 (2005), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Spinach (Spinacia oleracea) plants were grown under the day/night temperature regime of 15/10 °C (LT) or 30/25 °C (HT). The plants were also transferred from HT to LT when the sample leaves were at particular developmental stages (HL-transfer). With fully mature leaves, the light-saturated photosynthetic rate (A) at the ambient CO2 concentration (Ca) of 1500 µL L−1 (A1500) and the initial slope of A versus intercellular CO2 concentration (Ci) at low Ci region (IS) were obtained to assess capacities of RuBP regeneration and carboxylation. Photosynthetic components including Rubisco and cytochrome f (Cyt f) were also determined. The optimum temperatures for A at Ca of 360 µL L−1 (A360), A1500 and IS in HT leaves were 27, 36 and 24 °C, whereas those in LT leaves were 18, 30 and 18 °C. The optimum temperatures in HL-transfer leaves approached those of LT leaves with the increase in the duration at LT. The shift in the optimum temperature was greater and quicker for IS than A1500. By the HL-transfer, the maximum values of A1500 and IS also increased. The maximum A1500 and Cyt f content increased more promptly than IS and Rubisco content. Changes in the Cyt f/Rubisco ratio were reflected to those in the A1500/IS ratio. Taken together, photosynthetic acclimation to low temperature in spinach leaves was due not only to the change in the balance of the absolute rates of RuBP regeneration and carboxylation but also to the large change in the optimum temperature of RuBP carboxylation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3040.2004.01299.x
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  • 4
    Electronic Resource
    Electronic Resource
    Contributions of diffusional limitation, photoinhibition and photorespiration to midday depression of photosynthesis in Arisaema heterophyllum in natural high light (2000)
    Oxford, UK : Blackwell Science Ltd
    Plant, cell & environment 23 (2000), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Diurnal changes in photosynthetic gas exchange and chlorophyll fluorescence were measured under full sunlight to reveal diffusional and non-diffusional limitations to diurnal assimilation in leaves of Arisaema heterophyllum Blume plants grown either in a riparian forest understorey (shade leaves) or in an adjacent deforested open site (sun leaves). Midday depressions of assimilation rate (A) and leaf conductance of water vapour were remarkably deeper in shade leaves than in sun leaves. To evaluate the diffusional (i.e. stomatal and leaf internal) limitation to assimilation, we used an index [1–A/A350], in which A350 is A at a chloroplast CO2 concentration of 350 μmol mol−1. A350 was estimated from the electron transport rate (JT), determined fluorometrically, and the specificity factor of Rubisco (S), determined by gas exchange techniques. In sun leaves under saturating light, the index obtained after the ‘peak’ of diurnal assimilation was 70% greater than that obtained before the ‘peak’, but in shade leaves, it was only 20% greater. The photochemical efficiency of photosystem II (ΔF/Fm′) and thus JT was considerably lower in shade leaves than in sun leaves, especially after the ‘peak’. In shade leaves but not in sun leaves, A at a photosynthetically active photon flux density (PPFD) 〉 500 μmol m−2 s−1 depended positively on JT throughout the day. Electron flows used by the carboxylation and oxygenation (JO) of RuBP were estimated from A and JT. In sun leaves, the JO/JT ratio was significantly higher after the ‘peak’, but little difference was found in shade leaves. Photorespiratory CO2 efflux in the absence of atmospheric CO2 was about three times higher in sun leaves than in shade leaves. We attribute the midday depression of assimilation in sun leaves to the increased rate of photorespiration caused by stomatal closure, and that in shade leaves to severe photoinhibition. Thus, for sun leaves, increased capacities for photorespiration and non-photochemical quenching are essential to avoid photoinhibitory damage and to tolerate high leaf temperatures and water stress under excess light. The increased Rubisco content in sun leaves, which has been recognized as raising photosynthetic assimilation capacity, also contributes to increase in the capacity for photorespiration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-3040.2000.00547.x
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  • 5
    Electronic Resource
    Electronic Resource
    Nitrogen translocation via rhizome systems in monoclonal stands ofReynoutria japonica in an oligotrophic desert on Mt Fuji: Field experiments (1996)
    Springer
    Ecological research 11 (1996), S. 175-186 
    Details
    ISSN: 1440-1703
    Keywords: clonal plant ; nitrogen translocation ; physiological integration ; Reynoutria japonica ; volcanic desert
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Mechanisms which enableReynoutria japonica, a dominant pioneer herb, to be successful in maintaining large stands in an oligotrophic volcanic desert on Mt Fuji were investigated with special reference to its nitrogen acquisition.Reynoutria japonica forms circular stands, each of which comprises only one genet. As a stand develops outwards, the number of aerial shoots per unit area decreases in the center. Shoots grow vigorously in the peripheral area where the available nitrogen from soil and precipitation (about 2.4 g m−2 year−2) was much less than total nitrogen in the shoots (6.1–9.1 g m−2). Leaf nitrogen content per unit mass was also greater in the leaves of the peripheral shoots. When rhizomes extending radially from the center to the periphery were severed, the dry mass of shoots in the periphery diminished by 75% on a ground area basis. In the periphery, leaf nitrogen content also reduced significantly and no flowers were produced. When fertilizer was applied to the peripheral shoots with severed rhizomes, neither growth, survival nor flower production of the shoots was significantly smaller than the control levels. In these shoots, it is also found that the nitrogen content in the youngest leaves decreased for about 1 month and then increased to above that in the control leaves. These results suggest that (i) nitrogen accumulated in the central part is translocated to peripheral shoots via rhizomes, and that long-distance translocation enables the stands to develop outwards, and (ii) aerial shoots in the periphery utilize the nitrogen translocated by rhizomes in the beginning of the growth season, whereas once the shoots have established, they begin to take up nitrogen with their own roots. Since the peripheral shoots are in sunnier environments than the shoots inside the stand, the acropetal nitrogen translocation via rhizomes will raise the production efficiency of a whole stand.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02347683
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  • 6
    Electronic Resource
    Electronic Resource
    Effects of leaf age, nitrogen nutrition and photon flux density on the distribution of nitrogen among leaves of a vine (Ipomoea tricolor Cav.) grown horizontally to avoid mutual shading of leaves (1994)
    Springer
    Oecologia 97 (1994), S. 451-457 
    Details
    ISSN: 1432-1939
    Keywords: Distribution of leaf nitrogen content ; Leaf age ; Nitrogen availability ; Photon flux density Vine (Ipomoea tricolor)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Effects of leaf age, nitrogen nutrition and photon flux density (PFD) on the distribution of nitrogen among leaves were investigated in a vine, Ipomoea tricolor Cav., which had been grown horizontally so as to avoid mutual shading of leaves. The nitrogen content was highest in newly developed young leaves and decreased with age of leaves in plants grown at low nitrate concentrations and with all leaves exposed to full sunlight. Thus, a distinct gradient of leaf nitrogen content was formed along the gradient of leaf age. However, no gradient of leaf nitrogen content was formed in plants grown at a high nitrate concentration. Effects of PFD on the distribution of nitrogen were examined by shading leaves in a manner that simulated changes in the light gradient of an erect herbaceous canopy (i.e., where old leaves were placed under increasingly darker conditions with growth of the canopy). This canopy-type shading steepened the gradient of leaf nitrogen content in plants grown at a low nitrogen supply, and created a gradient in plants grown at high concentrations of nitrate. The steeper the gradient of PFD, the larger the gradient of leaf nitrogen that was formed. When the gradient of shading was inverted, that is, younger leaves were subjected to increasingly heavier shade, while keeping the oldest leaves exposed to full sunlight, an inverted gradient of leaf nitrogen content was formed at high nitrate concentrations. The gradient of leaf nitrogen content generated either by advance of leaf age at low nitrogen availability, or by canopy-type shading, was comparable to those reported for the canopies of erect herbaceous plants. It is concluded that both leaf age and PFD have potential to cause the non-uniform distribution of leaf nitrogen. It is also shown that the contribution of leaf age increases with the decrease in nitrogen nutrition level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00325881
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  • 7
    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
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  • 8
    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
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  • 9
    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
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  • 10
    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
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