Effect of GA3 on growth and chemical composition of jujube leaf (Ziziphus spina-christi) under salinity condition

In order to study the effects of GA3 on growth and the biochemical compositions of jujube (Ziziphus spina-christi) leaf، this experiment was conducted in 2011-2012، in department of horticultural science of faculty of agriculture Hormozgan University، Bandar abbas and nursery of Major Natural Recourses Office of Hormozgan province، as a factorial basis on completely randomized design with three replications. Experimental factors were 5 salinity levels (0، 1600، 3200 and 12800 ppm NaCl solutions) and 3 different concentrations of GA3 (0، 100 and 200 mg l-1). Seven weeks after GA3 application، leaf number and area، plant total dry weight، leaf Na+ and K+ concentrations، K+/Na+ and proline content were measured. Results indicated that with increasing NaCl concentrations leaf proline and Na+ were increased and other traits under study were decreased، significantly. Foliar application of GA3 alleviated the negative effects of salinity، so that under salinity conditions with foliar spray of GA3 (200 mg l-1) leaf number and area، total dry weight per plant، leaf K+ concentration and proline content were increased. GA3 reduced Na+ and increased K+ in the leaves which resulted in an increase in leaf K+/Na+. Results of this study revealed that foliar application of GA3 might increase jujube plants adoption to saline conditions via either reduction in Na+ absorption or by accumulation of K+ and proline in leaves.