EFFECT OF BENZYLADENINE ON PEROXIDASE-ACTIVITY DURING SENESCENCE OF SUNFLOWER (HELIANTHUS-ANNUUS L) COTYLEDONS

The influence of benzyladenine (BA, a cytokinin) on peroxidase activit y during the senescence of sunflower cotyledons was investigated. For this purpose, changes in the activity of peroxidase were determined du ring senescence of the cotyledons by spectrophotometric method and the effect of BA on peroxidase isoenzymes was determined by polyacrylamid e gel electrophoresis. However, the level of total chlorophyll was mea sured as the sign of senescence. While the senescence stage of cotyled ons progressed, peroxidase activity was found increasing, whereas ther e was a decline in the level of total chlorophyll. In the BA-treated c otyledons, the activity of peroxidase and the number of isoperoxidases decreased compared with the control whereas the level of total chloro phyll was higher than the control. From these results, it was conclude d that reduced peroxidase activity in the BA-treated cotyledons was a contributing mechanism to the overall antisenescence action of cytokin ins, if not at least a close relationship.