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  • 1
    Electronic Resource
    Electronic Resource
    Quantitative analysis of abscisic acid in needles of Abies alba Mill. by electron capture gas chromatography (1993)
    Springer
    Trees 7 (1993), S. 175-181 
    Details
    ISSN: 1432-2285
    Keywords: Abies alba ; Abscisic acid ; Damage ; Gas chromatography ; Needles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The amount of abscisic acid (ABA) in needles of silver fir from a natural location was investigated with regard to position in the crown, damage, seasonal variation, and needle age. Because of problems of quantification of ABA in coniferous needles, which contain numerous secondary plant products, a method for reliable determination of both isomers cis-trans-ABA (c-ABA) and transtrans-ABA (t-ABA) was developed. By means of gas chromatography (GC) using an electron capture detector (BCD) and a programmed temperature vaporizer (PTV) injector complete separation of both compounds was achieved. Two different pairs of fir were investigated — in each case a damaged and a healthy tree. Needles from both trees from the first and the second pair collected in September contained 500–1100 ng c-ABA/g fresh weight (FW), and the concentrations of t-ABA varied from 400 to 700 ng/g FW. Investigations from the second pair show highest amounts of 2900 ng/g Fw c-ABA and 1800 ng/g FW of t-ABA in May and June. For the first pair a higher c-ABA content was found in needles from the top of the crown than in those from the middle and the base. This difference could not be confirmed in the analysis of the second pair. Because of the strong natural deviation no statistically significant difference between the healthy and the damaged tree was found. The first pair of firs examined showed a higher t-ABA concentration than the second one. In this case the highest amount was found in the top of the crown. Methodical mistakes during the clean-up procedure and in quantification by gas chromatography could be excluded. The presence of c- and t-ABA in the purified extract was corroborated by mass spectrometry. With regard to the seasonal variation both isomers of ABA show an unequivocal trend. The maximum concentration is achieved in May to June, whereas the content is minimal in August/September. In any case the level of t-ABA is lower than that of c-ABA. No correlation between the amount of ABA and the needle age could be established.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00199619
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  • 2
    Electronic Resource
    Electronic Resource
    Lipids and lipolytic enzymes in the trunkwood ofRobinia pseudoacacia L. during heartwood formation (1996)
    Springer
    Trees 10 (1996), S. 366-375 
    Details
    ISSN: 1432-2285
    Keywords: 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 ofRobinia 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, diand 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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  • 3
    Electronic Resource
    Electronic Resource
    Determination of phytohormones in phloem exudate from tree species by radioimmunoassay (1981)
    Springer
    Planta 152 (1981), S. 168-170 
    Details
    ISSN: 1432-2048
    Keywords: Abscisic acid ; Auxin ; Cytokinin ; Gibberellin ; Phloem exudate ; Radioimmunoassay (phytohormones) ; Trees (phytohormones)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A sensitive and specific radioimmunoassay was used to determine quantitatively four of the most important phytohormones in the phloem exudate from 14 different tree species of 8 genera. For cytokinins and indole-3-acetic acid (IAA) we found higher concentrations than those reported previously for other species. The gibberellin values were of the same order of magnitude as in earlier analyses (with different methods) of tree phloem exudates, but lower than the ones reported for Ricinus. Free abscisic acid (ABA) was found in tree phloem exudates in similar concentrations as before in Yucca or palm phloem exudate, but at considerably lower ones than reported for Ricinus and in Lupinus phloem exudate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00391189
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