| Abstrakt: |
Imbibing `Grand Rapids' lettuce (Lactuca sativa L.) seeds take up 14C-kinetin, and metabolize this cytokinin to the 5'-nucleotide. The identity of the labeled nucleotide in seed extracts was verified by Sephadex LH-20 column chromatography, paper and thin layer chromatography, and high voltage paper electrophoresis. Incubations with kinetin in the presence of abscisic acid lead to an apparent specific inhibition of kinetin nucleotide formation. ABA has no effect on kinetin uptake, and does not inhibit kinetin nucleotide synthesis in vitro by a cell free preparation from lettuce seeds. Additionally, ABA does not inhibit adenylate synthesis from exogenously supplied adenine. These results represent a specific cytokinin-ABA interaction, which might play a significant role in the hormonal regulation of lettuce seed germination. [ABSTRACT FROM AUTHOR] |
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