Effect of GA3, kinetin and indole acetic acid on carbohydrate metabolism in chickpea seedlings germinating under water stress

Enhanced amylase activity was observed during a 7-day-growth period in the cotyledons of PEG imposed water stressed chickpea seedlings grown in the presence of GA₃ and kinetin, when compared with stressed seedlings. During the first 5 days of seedling growth, the seedlings growing under water deficit conditions as well as those growing in the presence of PGRs had a higher amylase activity in shoots than that of control seedlings. Neither GA₃ nor kinetin increased the amylase activity of roots whereas IAA reduced root amylase activity. Activity of acid and alkaline invertases was maximum in shoots and at a minimum in cotyledons. Compared with alkaline invertase, acid invertase activity was higher in all the tissues. The reduced acid and alkaline invertase activities in shoots of stressed seedlings were enhanced by GA₃ and kinetin. Roots of stressed seedlings had higher alkaline invertase activity and GA₃ and IAA helped in bringing the level near to those in the controls. GA₃ and kinetin increased the sucrose synthase (SS) and sucrose phosphate synthase (SPS) activities in cotyledons of stressed seedlings, whereas they brought the elevated level of SPS of stressed roots to near normal level. The higher level of reducing sugars in the shoots of GA₃ and kinetin treated stressed seedlings could be due to the high acid invertase activity observed in the shoots, and the high level of bound fructose in the cotyledons of stressed seedlings could be due to the high activity of SPS in this tissue.