Combined effects of salinity and drought on physiological and biochemical characteristics of pistachio rootstocks

In the current research, four seven-month-old pistachio rootstocks named UCB-1, Badami, Ghazvini and Kale-Ghouchi were exposed to control, drought, salinity and drought + salinity conditions for eight weeks. Considering the results of this research, in all studied pistachio rootstocks, Na+ and Cl- increased, while K+ decreased under drought and salinity, alone or in combination. Also, under drought, salinity and drought + salinity in all studied pistachio rootstocks and compared to the control environment, ascorbate peroxidase, polyphenol oxidase, catalase and guaiacol peroxidase enzymes activities and contents of electrolyte leakage, malondialdehyde, other aldehydes, hydrogen peroxide, proline, total free amino acids and total soluble carbohydrates were elevated, while the content of protein decreased with the largest impact which was visible under combined stress. In this study, a positive correlation was observed between the amount of K+ and antioxidant enzymes activities. Other correlations that were observed were negative correlations between the hydrogen peroxidase content and the amounts of proline, total free amino acids, total soluble carbohydrates and total soluble proteins. Based on the bi-plot and cluster analyses and other outcomes, UCB-1 > Badami > Ghazvini > Kale-Ghouchi pistachio rootstocks are arranged from resistant to sensitive cultivars under alone or combination of drought and salinity stresses. Altogether, the destructive effects of different aforementioned environments can be arranged as follows: drought + salinity > salinity > drought.