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  • Articles  (142)
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  • 11
    Electronic Resource
    Electronic Resource
    Partition coefficients of plant cuticles for monoterpenes (1992)
    Springer
    Trees 6 (1992), S. 32-36 
    Details
    ISSN: 1432-2285
    Keywords: Abies ; Cuticle ; Monoterpene ; Octanol/water partition coefficient ; Picea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Cuticle/water partition coefficients (Kc/w) for d-limonene, α-pinene and β-pinene were determined by an extrapolation and a desorption method. The sorption experiments were carried out with isolated angiosperm and gymnosperm cuticles and with [14C]-labelled monoterpenes, which were obtained biosynthetically. Both methods were suitable for the determination of the Kc/w of volatile hydrophobic compounds. For the angiosperm cuticles the partition coefficients are of the order of 104, which indicates a high accumulation of monoterpenes in the cuticle. The values of the conifer cuticles of Picea abies (L.) Karst. and Abies alba Mill., however, are lower due to their high lignin content. This is proved by the increase of the partition coefficients after removal of polar and phenolic components. The Kc/w can be estimated with good accuracy from the octanol/water partition coefficient, which was determined experimentally.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224496
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  • 12
    Electronic Resource
    Electronic Resource
    Pyridine nucleotide levels and activities of dehydrogenases in cambial derivatives of Robinia pseudoacacia L . (1996)
    Springer
    Trees 10 (1996), S. 325-330 
    Details
    ISSN: 0931-1890
    Keywords: Key words Cambial differentiation ; Glucose-6-phosphate dehydrogenase ; 6-Phosphogluconate dehydrogenase ; NAD kinase ; Pyridine nucleotides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  Despite the importance of the vascular cambial differentiation, little is known about its regulation. In order to address this problem we attempted to biochemically characterize differentiating xylem and phloem elements during the early stages of development. By applying techniques of quantitative histochemistry we show that the total pool size of pyridine nucleotides is similar in the phloem (PD) and xylem (XD) oriented derivatives of the cambial zone of trees of Robinia pseudoacacia L. Within the PD zone, the amount of NAD + NADH exceeded that of NADP + NADPH [around 600 versus 200 pmol (mg dry weight)–1], possibly indicative of a preponderance of catabolic pathways (ratio of NADH : NAD about 1). In contrast, the NADP(H) system dominated in the XD zone. This coincided with a high activity of NAD kinase. In addition, the extractable activities of the key enzymes of the oxidative pentose phosphate pathway, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase, were greatly increased. At a ratio of NADPH : NADP of approximately 1, this could be indicative of increased rates of reductive biosyntheses, and could thus well be involved in early steps of the formation of phenols and lignin monomers. Taken together, this first approach clearly shows that phloem-oriented and xylem-oriented cambial descendents exhibit distinct differences in their biochemical patterns even in early stages of differentiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00009652
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  • 13
    Electronic Resource
    Electronic Resource
    Lipids and lipolytic enzymes in the trunkwood of Robinia pseudoacacia L . during heartwood formation (1996)
    Springer
    Trees 10 (1996), S. 366-375 
    Details
    ISSN: 0931-1890
    Keywords: Key words Acyllipids ; Heartwood formation ; Phospholipids ; Robinia pseudoacacia L. ; Sterols
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  The radial distribution of membrane and storage lipids was determined in the trunkwood of Robinia pseudoacacia L. The trees were felled in November at the time of heartwood formation and fluctuations in the amount and composition of phospholipids, free sterols, steryl esters, di- and triacylglycerols, and free fatty acids were investigated across the sapwood-heartwood boundary. The individual compounds were identified and quantified by thin layer chromatography, enzymatic and colorimetric assays, and by capillary gas chromatography. Phospholipids show a significant decrease towards the boundary area, and in the heartwood only trace amounts can be detected. The same pattern is observed for free sterols in the sapwood; in the heartwood, however, they reach maximum values with increasing depth of the trunk. Steryl esters exhibit a complementary behaviour by accumulating at the periphery of the heartwood. No concentration changes are found in the total amounts of diacylglycerols and free fatty acids. In contrast, the triacylglycerol concentration declines steadily across the trunk. With regard to qualitative composition, free fatty acids and the fatty acid moieties of the esterified constituents vary in their chain length from 14 to 24 carbon atoms and have up to three double bonds. A radial gradient in the ratio saturated/unsaturated fatty acids can be observed: except for the phospholipid fraction the relative amounts of unsaturated fatty acids increase in centripetal direction. Seven phospholipids were identified: phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, diphosphatidylglycerol, and phosphatidic acid, which constitutes the major proportion. In the sterol group, sitosterol is the most abundant component. The composition of the esterified sterols remains constant across the trunk cross-section, whereas the relative frequencies of individual free sterols change markedly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02185640
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  • 14
    Electronic Resource
    Electronic Resource
    Lipids and lipolytic enzymes in the trunkwood of Robinia pseudoacacia L . during heartwood formation (1996)
    Springer
    Trees 10 (1996), S. 376-381 
    Details
    ISSN: 0931-1890
    Keywords: Key words Acylesterhydrolase ; Heartwood formation ; Lipase ; Robinia pseudoacacia L. ; Phospholipases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  The radial profile of lipase and phospholipase activities was determined in the trunkwood of Robinia pseudoacacia L. The trees were felled in November at the time of heartwood formation and alterations in the enzymatic activities were investigated across the sapwood and heartwood. Methods employed include gaschromatographic, colorimetric and enzymatic assays. On a dry weight basis, the hydrolysis of the artificial substrate p-nitrophenylpalmitate shows a maximum activity in growth ring 4; however, the assay has proved not to be specific for lipase. In contrast, lipase analyses (triacylglycerol acylhydrolase; E.C. 3.1.1.3) with an authentic substrate show activity peaks in growth rings 1 and 4. With protein as a reference the highest activity is found in growth ring 5. A similar tendency is observed for phospholipase A1 (E.C. 3.1.1.32) and phospholipase A2 (E.C. 3.1.1.4). Phospholipase C (E.C. 3.1.4.3) activity decreases towards the sapwood-heartwood boundary; negligible traces of activity are detected in the heartwood, whereas, based on the protein content, growth ring 4 yields maximal activity. Phospholipase D (3.1.4.4) exhibits the same radial pattern with regard to protein content as a reference. On a dry weight basis there is a significant increase within the sapwood area, while in the heartwood the activity drastically decreases. The enzyme activities are discussed in relation to degradative processes within the plasma membranes and the hydrolysis of reserve lipids during heartwood formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02185641
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  • 15
    Electronic Resource
    Electronic Resource
    Photosynthesis of mistletoes in relation to their hosts at various sites in tropical Brazil (1998)
    Springer
    Trees 12 (1998), S. 167-174 
    Details
    ISSN: 0931-1890
    Keywords: Key words Aluminium ; Carbon isotope ratios ; Cerrado ; Chlorophyll fluorescence ; Mistletoes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  Chlorophyll a fluorescence parameters showing the instantaneous performance and carbon-isotope ratios reflecting long-term behaviour of leaves were determined for a large number of mistletoe/host-pairs in the cerrado belt of Brazil. Study sites were a very exposed rupestrian field, a semi-exposed savanna and a highly shaded gallery forest. The major question asked was if photosynthetic capacity of mistletoe leaves differed from that of the leaves of their respective hosts. It is shown that except for the very exposed rupestrian field site, photosynthetic capacity appeared to be similar in mistletoes and host leaves. The superior behaviour of host leaves in the rupestrian field was due to particularly expressed sun-plant characteristics of the host. However, mistletoes always had higher average stomatal conductances, lower leaf temperatures at similar or even higher irradiance and higher intercellular CO2-partial pressures than hosts. Photosynthetic performance of mistletoe leaves was independent of whether a given mistletoe species parasitized aluminium-accumulating or non-accumulating host species in the cerrados with their aluminium-rich soils.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004680050136
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  • 16
    Electronic Resource
    Electronic Resource
    Biomass production of C3- and C4-plant species in pure and mixed culture with different water supply (1981)
    Springer
    Oecologia 50 (1981), S. 73-81 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Pure and mixed cultures of the dicotyledons Atriplex hortensis L. (C3 plant) and Amaranthus retroflexus L (C4) on the one hand and of the grasses Avena sativa L (C3) and Panicum miliaceum L. (C4) on the other hand were maintained in a standard soil with different ground water tables. After 12 weeks the length, dry weight and nitrogen-content of the aboveground and belowground parts of the plants, and in addition the carbon-and ash-content and the δ13C value of the aboveground parts were determined. It turned out that the length and the dry weight of the shoots of the C3 species showed on increasing tendency with increased water supply, while the values of the C4 species were drastically diminished at the highest water level only. The roots showed in most cases an increased length and dry weight at drier conditions, more pronounced in the C4 than in the C3 species. The nitrogen content of the shoots was mostly higher in the shoots of the C3 plants and in the roots of the C4 plants; it changed in a non-regular manner with variations in water supply. Since the carbon content did not change markedly, the C/N ratio was variable. There was a slight tendency for a higher carbon content and mostly also for a higher C/N-ratio in the shoots of C4 plants. The δ13C values of both C3 as C4 plants were in general not at all influenced by the water supply; they were fixed genetically. The ash content of the analyzed species did not show a clear relationship to the type of photosynthetic CO2-fixation or to the water regime. The influence of light intensity was studied with mixed cultures of all four plant species, again with different water supply. There was a strong effect of light intensity on the competitive behaviour of the C3 and C4 plants under modified water conditions. The wild C3 plant Atriplex hortensis was most successful under conditions of relatively low light intensity and high water availability, while the cultivated ‘artificial’ species Avena sativa showed much less differences between full-light grown and shadow plants. The C4 plant Amaranthus retroflexus is most successful under competitive conditions at high water stress in full light. The C4 grass Panicum miliaceum showed maximum shoot growth in light, but was successful under competitive conditions especially also with good water supply. The light intensity had no effect on the δ13C values. — There was no indication that the soil-type as such has a distinct influence on the success of C3 or C4 plants in mixed cultures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00378796
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  • 17
    Electronic Resource
    Electronic Resource
    Mechanisms of stomatal movement in response to air humidity, irradiance and xylem water potential (1991)
    Springer
    Planta 183 (1991), S. 57-64 
    Details
    ISSN: 1432-2048
    Keywords: Cell water status ; Cuticle ; Gas exchange ; Humidity (vapor-pressure difference) ; Stomatal movement ; Tradescantia (stomatal movement) ; Water stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Turgor, and osmotic and water potentials of subsidiary cells, epidermal cells and mesophyll cells were measured with a pressure probe and a nanoliter osmometer in intact transpiring leaves of Tradescantia virginiana L. Xylem water potential was manipulated by changing air humidity, light, and water supply. In a transpiring leaf the water potential of mesophyll cells was lower, but turgor was higher, than in cells surrounding the stomatal cavity owing to the presence of a cuticle layer which covers the internal surface of subsidiary and guard cells. Cuticular transpiration from the outer leaf surface was negligibly small. When stomata closed in dry air, transpiration decreased despite an increasing vapor-pressure difference between leaf and air, and the water potential of subsidiary cells dropped to the level of the water potential in mesophyll cells. We suggest that the observed decrease of transpiration at increasing vapor-pressure difference can be attributed to a shortage of water supply to the guard cells from subsidiary cells, causing turgor to decrease in the former more than in the latter. The leafs internal cuticle appears to play a special role in channelling the internal water flow during a water shortage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00197567
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  • 18
    Electronic Resource
    Electronic Resource
    Über die Atmung und den Stofftransport in den Isolierten Leitbündeln der Blattstiele von Heracleum MantegazzianumSomm. etLev (1958)
    Springer
    Planta 51 (1958), S. 186-200 
    Details
    ISSN: 1432-2048
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01912058
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  • 19
    Electronic Resource
    Electronic Resource
    Untersuchungen Über die Leitung und Sekretion der Assimilate (1956)
    Springer
    Planta 47 (1956), S. 447-500 
    Details
    ISSN: 1432-2048
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01935416
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  • 20
    Electronic Resource
    Electronic Resource
    Über die Zusammensetzung des “Bestäubungstropfens” und den Mechanismus seiner Sekretion (1959)
    Springer
    Planta 52 (1959), S. 587-599 
    Details
    ISSN: 1432-2048
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Zusammenfassung der Ergebnisse 1. Der Bestäubungstropfen vonTaxus baccata enthält an Zuckern Saccharose, Glucose und Fructose; die Konzentration der Aminosäuren (10 frei und 6 in einem oder mehreren Peptiden gebunden) und des Phosphats ist relativ hoch (etwa in der Größenordnung der bisher analysierten Siebröhrensäfte). Äpfelsäure und Citronensäure sind nachweisbar. 2. Im Bestäubungstropfen vonEphedra helvetica findet sich als einziger Zucker Saccharose; auch hier ist die Konzentration der Aminosäuren (8 frei und 12 in einem oder mehreren Peptiden) und des Phosphats hoch. 3. Der Bestäubungstropfen vonTaxus baccata wird auch nach völliger Hemmung der Atmung abgeschieden; es handelt sich also dabei nicht um eine aktive Sekretion. Eine Beteiligung der Mikropyle an der Abscheidung konnte ausgeschlossen werden. 4. Im wasserdampfgesättigten Raum zeigen auch Pinaceen (Picea excelsa undLarix leptolepis) einen Tropfenaustritt aus der Mikropyle; ob dieser auch unter natürlichen Bedingungen eine Rolle spielt, bleibt zu klären.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01914757
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