Endogenous Levels of Cytokinins in Ageing Cucumber Cotyledons

Abstract

There are several procedures for isolating cytokinins which involve a number of steps including extraction, solvent fractionation and column or paper chromatography. Various combinations of these procedures were tried in an attempt to isolate cytokinins from cucumber cotyledons. It was found that with this tissue it was preferable to omit a few steps to minimize the loss, of cytokinins activity. The endogenous cytokinin levels in etiolated cucumber cotyledons of different ages were estimated and compared with the capacity of the cotyledons to produce chlorophyll after exposure to light. There was a parallel relationship between cytokinin levels and chlorophyll production. The cytokinin levels were highest in 8 day old cotyledons, at which time the production of chlorophyll was also maximal. It is proposed that cytokinins have an important role in chlorophyll production