Cytokinin Translocation: Changes in Zeatin and Zeatin-riboside Levels in the Root Exudate of Tomato Plants during their Development

The zeatin and zeatin riboside content of tomato (Lycopersicon esculentum Mill.) root exudates were determined at different stages of development. Zeatin riboside was found to be the major translocational form of cytokinin in the xylem during early vegetative growth. During flower bud formation this cytokinin decreased markedly in concentration so that, at anthesis, there was no appreciable difference in the zeatin and zeatin riboside concentration in the root exudate.