title: Cytokinin Biochemistry in Relation to Leaf Senescence: IV. Cytokinin Metabolism in Soybean Explants.
abstract: When [(3)H]dihydrozeatin riboside and [(3)H]zeatin riboside were supplied to soybean (Glycine max L.) explants (comprising one leaf, associated pods, and subtending stem) via the xylem at mid to late podfill, 0.1% of the supplied (3)H was extracted from the seeds. The distribution of (3)H in the explants was similar to that bound previously following uptake of [(3)H]zeatin riboside at earlier stages of pod development. Metabolites formed in the explants from (3)H-labeled zeatin, zeatin riboside, and dihydrozeatin riboside were identified and related to the endogenous cytokinins shown to be present. When zeatin riboside and zeatin were supplied for 1 hour, zeatin nucleotide was the principal metabolite formed and this appeared to be the precursor of the other metabolites detected subsequently. Explants supplied with zeatin riboside or dihydrozeatin riboside for 1 hour, and then transferred to water for 20 to 24 hours, yielded leaf blades in which the main metabolites were O-glucosyldihydrozeatin, adenosine, and adenine. The metabolism of zeatin riboside in blades of explants at pre-podfill, early podfill, and mid to late podfill did not differ appreciably. The results are discussed in relation to leaf senescence and seed development.
authors: Plant Cell Biology Group, Research School of Biological Sciences, The Australian National University, PO Box 475, Canberra City, ACT, 2601, Australia.
authors: S
authors: S
authors: Singh
authors: D S
authors: DS
authors: Letham
authors: P E
authors: PE
authors: Jameson
authors: R
authors: R
authors: Zhang
authors: C W
authors: CW
authors: Parker
authors: J
authors: J
authors: Bandenoch-Jones
authors: L D
authors: LD
authors: Noodén