Effect of Gibberellic Acid and Nitrogen on Micronutrients Concentration of Pistachio Seedling under Salinity Conditions

In order to investigate the effect of gibberellic acid and nitrogen on the length of root system and micronutrients concentration of pistachio seedlings in saline conditions (cv. Badami Zarand), a factorial greenhouse experiment was carried out as a completely randomized design (CRD) with three replications. Treatments consisted of two salinity levels (0 and 1200 mg NaCl per kg soil), two nitrogen levels (0 and 150 mg N kg-1 soil as NH4No3) and two levels of gibberellic acid hormone (0 and 75 mg l-1). Results showed that although salinity significantly decreased the length of root system, the application of 75 mg per liter gibberellic acid in this saline conditions increased the length of root system 36 percent compared to control. Also, the application of 75 mg per liter gibberellic acid in saline conditions increased the concentration of Cu, Zn and Fe in shoot by 58, 44 and 65 percent, respectively. Combined application of nitrogen and gibberellic acid increased the concentration of Cu and Fe in shoot more than 2 folds compared to control. Also, combined application of nitrogen and gibberellic acid increased Cu and Zn concentrations more than 2 folds and Fe concentration increased 52 percent compared to control. The results also showed that in saline conditions, the highest concentrations of Cu, Mn and Fe by shoot and Zn by root was observed with the combination of nitrogen and gibberellic acid. According to the results, in the end of it can be concluded that the combination application of nitrogen and gibberellic acid was more effective in reducing the detrimental effects of salinity than the use of these treatments alone.