Hydrogen peroxide-induced salt tolerance in relation to antioxidant systems in pistachio seedlings

In this study, the effects of H2O2 pretreatment on growth and antioxidant system were investigated in pistachio rootstock Badami Rize Zarand during short term salt stress. The plants were subjected to NaCl stress (120 or 240 mM) for 7 days after pretreatment with 0, 1, 5 or 10 mM H2O2. Salinity stress significantly decreased seedling growth and ascorbic acid (ASA) and carotenoid (CAR) contents, whilst exogenous H2O2 application improved the growth and helped to reduce the percent reduction of total ASA and CAR contents under salt stress conditions. Ascorbate peroxidase (APX) and catalase (CAT) activities were strongly induced by salt stress after 48 h and reached the highest level at 168 h after spraying. H2O2-treated plants showed enzymatic activity higher than untreated plants, during the entire experimental period. Salinity treatments caused increase in plants GSH content with or without H2O2 pretreatment. GSH levels in the plants were previously treated with H2O2 were elevated even higher. Overall, better performance of pistachio seedlings under salt stress due to H2O2 pre-treatment might be due to improved better osmotic adjustment through coordination with CAT, and APX and enhanced non-enzymatic antioxidant accumulation under salt stress leading to a higher ability to withstand salt-induced effects.