Department of Botany, Plant Physiology and Biochemistry Lab., Universtiy of Calcutta, Calcutta-700 019
Cytokinins released from t-RNA hydrolysates at different stages of germination in leaf were analysed using DEAE cellulose and Sephadex LH-20 columns coupled with soybean callus bioassay. Cytokinins having elution pattern similar to dihydrozeatin, zeatin and isopentenyleadenine were detected in dry, mature seeds (O h) and at 24, 48, 72 and 96 h. following imbibition. From 48 to 96 h after imbibition the peak of dihydrozeatin was absent in tRN A hydrolysate. The cytokinin activity of zeatin and isopentenyladenine increased gradually from (O h) and reached its maxima at 72 h and dropped appreciably at 96 h following imbibition. The significance of the finding is discussed in relation to turnover rates of cytokinins.
