Effect of BA and ABA on enzymes and chlorophyll in dark incubated detached leaves of sunflower (Helianthus annuus, L.)

The effect of abscisic acid (ABA) and benzyladenine (BA) on dark induced senescence of sunflower leaves has been studied with reference to the changes in the levels of the enzymes involved in nitrogen metabolism. Senescence in dark led to loss of chlorophyll, but increased protease, glutamate dehydrogenase and aspartic aminotransferase (GOT) activities. Abscisic acid further increased the loss of chlorophyll, protease and glutamate dehydrogenase activity. Benzyladenine, on the other hand reduced the loss of chlorophyll and decreased the glutamate dehydrogenase and protease activities.