8-14C-Zeatin metabolites and their transport from leaf to phloem exudate of Yucca [free and bound cytokinins, cytokinin metabolism and transport, Yucca flaccida]
1981
Vonk, C.R. | Davelaar, E. (Centre for Agrobiological Research, Wageningen (Netherlands))
Transport and metabolism of 8-('14)C-zeatin, applied to an attached de-tipped one-year-old mature leaf of a Yucca plant bearing a bleeding inflorescent stalk, has been studied. Radioactive zeatin ribotide was found in the exudate of the bleeding inflorescence, which was collected over a period of 5 days. Radioactive zeatin riboside was mainly extracted from the fed leaf. Minor conversion products in this leaf were zeatin ribotide, zeatin-o-beta-glucoside and zeatinriboside o-beta-glucoside. In not zeatin fed plants, zeatin-o-beta-glucoside was tentatively identified as the main endogenous cytokinin in one-year-old mature leaves. In the bleeding sap of not treated plants no free bases of zeatin or zeatin ribosides were found. After alkaline phosphatase treatment zeatin-riboside was detected by combined gas chromatography-mass spectrometry, indicating the presence of zeatin ribotide in the bleeding sap. High beta-glucosidase activity was found in the stem. Results suggest that stored cytokinin glucosides from Yucca leaves are, converted by beta-glucosidase in leaves and stem, transported through the inflorescent stalk as zeatin nucleotides
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