Cytokinins extracted from Pinto bean fruit

Extracts from various parts of Phaseolus vulgaris L. var. Pinto plants were found to exhibit cytokinin activity with the highest levels present in extracts of the fruit tissue. To separate the cytokinins present in the fruit, extracts were chromatographed in several solvent systems. Bioassays of chromatograms indicated the presence of active factors in those regions of migration associated with several known N-6-substituted aminopurines. Ultraviolet and mass spectral studies confirm the presence of a mixture of N-6-substituted aminopurines in the active material isolated by cation exchange resin chromatography. The evidence strongly supports the conclusions that dihydrozeatin is naturally occurring as the free base and possibly as a ribonucleoside. Further, zeatin appears to occur mainly as a glycosidic compound which is altered by KMnO4 treatment and is hydrolyzed under acid conditions.