Short-term effects of cytokinins on the lipid fatty acids of green leaves

Abstract

Isolated shoots of Coleus blumei and isolated leaves from this species and from Impatiens sultani were fed zeatin for different periods. High doses of the hormone (100 μg/ml) caused a measurable effect on lipid fatty acid composition after a two-hour feeding period in isolated leaves of Coleus. The maximum effects were at 20–30 μg zeatin taken up per g fresh weight. With the leaves of Impatiens, higher doses of the hormone were needed to obtain optimal effects. In both species, the proportion of linolenic acid increased and that of palmitic acid decreased. For higher concentrations, the reverse was true. The effects of the hormone on the fatty acids of glycolipids were more apparent than on those of phospholipids. The results are discussed in view of the general importance of dose-response curves for cytokinin effects and the possible effects on cell membranes.