خيارات البحث
النتائج 1 - 2 من 2
Nutritional aspects of forest soil structure
1989
Hildebrand, E.E. (Forstliche Versuchs- und Forschungsanstalt Baden-Wuerttemberg, Freiburg (Germany, F.R.).)
Cytokinin content and metabolism in Norway spruce as influenced by environmental stress
1995
Bettin, D. | Matzad, H. | Hahn, H. (Hamburg Univ. (Germany). Institut f. Angewandte Botanik) | Von-Schwartzenberg, K. (Institut National de la Recherche Agronomique, Versailles (France)) | Doumas, P. (Institut National de la Recherche Agronomique, Olivet (France))
It was our aim to investigate whether the cytokinin status of Norway spruce seedlings (Picea abies L. Karst.) was changed when the plants were grown under nutritive stress. Cytokinins in shoots and roots from spruce seedlings, grown in various hydrocultural media with complete (control) or poor nutrient supply (stress), were determined by an indirect competitive enzyme-liked immunosorbent assay. The shoots of spruce seedlings grown in a poor acidic culture medium, to which aluminium ions (AlCl3, 0.8 mM) were added, showed up to 5-fold higher concentrations of zeatin riboside and isopentenyladenosine (iPa). When adding naphtylacetic acid to the nutrient medium also higher levels of cytokinin ribosides were measured in the shoots. In the roots however cytokinin riboside levels did not increase significantly under Al- or auxin treatment. Feeding experiments using tritiated iPA have shown that the metabolism of this cytokinin is strongly retarded in the roots of stressed seedlings. The experiments show that acid conditions and nutrient shortage together with aluminium ions in the rhizosphere increase the number of lateral roots in Norway spruce seedlings. It is assumed that the increased number of sites of cytokinin biosynthesis and the reduced metabolism of iPA result in the higher content of cytokinin ribosides in the shoots of seedlings.
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