Exogenous hydrogen peroxide can enhance tolerance of wheat seedlings to salt stress

Hydrogen peroxide (H2O2), an active oxygen species, is widely generated in many biological systems and mediates various physiological and biochemical processes in plants. In this study, we demonstrated that exogenous H2O2 was able to improve the tolerance of wheat seedlings to salt stress. Treatments with exogenous H2O2 for 2 days significantly enhanced salt stress tolerance in wheat seedlings by decreasing the concentration of malondialdehyde (MDA), the production rate of superoxide radical (O2−), and increasing the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX), and the concentration of glutathione (GSH) and carotenoids (CAR). To further clarify the role of H2O2 in preventing salt stress damage, CAT and ascorbate (AsA), the specific H2O2 scavengers, were used. The promoting effect of exogenous H2O2 on salt stress could be reversed by the addition of CAT and AsA. It was suggested that exogenous H2O2 induced changes in MDA, O2−, antioxidant enzymes and antioxidant compounds were responsible for the increase in salt stress tolerance observed in the experiments. Therefore, H2O2 may participate in antioxidant enzymes and antioxidant compounds induced tolerance of wheat seedlings to salt stress. The results also showed that exogenous H2O2 had a positive physiological effect on the growth and development of salt-stressed seedlings.