Presence of a cytokinin binding protein in ungerminated barley embryos.
Cytokinins, a group of plant hormones, at very low concentrations regulate a wide variety of growth processes in plantsu. The activity of these compounds is determined by their structural and often stereoscopic properties, and even a subtle change in the structure, results in a drastic change in activity 3 .4. Hypotheses are advanced for the action of cytokinins at the level of gene expression 5. However the precise mechanism of action of these hormones in triggering various physiological activities is not known. Since it is generally felt that only proteins are able to recognise subtle structural differences, it is assumed that plant hormones, like animal hormones, bind with some proteins in order to initiate the biochemical events leading to physiological responses 3 . Recently, much attention is being paid to detect, isolate and characterise hormone receptor proteins in plants 6 11 .