Exogenous salicylic acid alleviates the oxidative damage of arabidopsis thaliana by enhancing antioxidant defense systems under high light

Abstract

To understand the protective roles of salicylic acid (SA) under high light, we investigated oxidative damage of Arabidopsis thaliana under high light in the presence or absence of SA. The results indicate that the high light led to an increase in the levels of proline, soluble sugars, reactive oxygen species, malondialdehyde, and electrolyte leakage, and a decrease in stomatal conductance (gs). Activities of six antioxidant enzymes increased significantly under the high light for 1 h. However, the high light for 3 h decreased the activities of peroxidase, superoxide dismutase, and catalase. In addition, we found that exogenous SA effectively improved antioxidant enzyme activities and significantly alleviated ROS accumulation and cell death in A. thaliana under the high light. Therefore, our results show that the high light caused a severe oxidative damage, and SA effectively alleviated the adverse effects of the high light on the plants by regulating the antioxidative defense system.