Cytokinins in Germinating Seeds of Phaseolus vulgaris L. I. Changes in Endogenous Levels Within the Cotyledons

Publisher Website
Google Scholar
Abstract
Ethanolic extracts from the cotyledons of mature dry Phaseolus vulgaris L. seed yielded cytokinin-like activity which co-chromatographed with zeatin and ribosylzeatin. Under conditions which stimulated germination and cotyledon expansion, the level of these cytokinins decreased rapidly in both intact embryos and excised cotyledons. In the excised cotyledons the decrease was continuous, resulting in very low levels of cytokinin being detected after 4 days of incubation. With the embryonic axis present, however, the initial decrease was arrested and reversed after 3 days. This suggests that the cotyledons do not synthesize cytokinins but that these hormones are imported from the embryonic axis, particularly once radicle growth is well under way.