Abstract

Salicylic acid (SA) is a promising phenolic compound to increase plant tolerance to drought stress, and it can affect many aspects of physiological (enzyme activity) and biochemical processes (proline content) of plant. The effects of salicylic acid under drought stress on wheat were evaluated in the vegetation stages in the greenhouse of Washington State University (Pullman, USA) during 2019. The leaves of wheat treated by salicylic acid. The degree of soil moisture was measured during the experiment by soil moisture sensors. Antioxidant enzymes (ascorbate peroxidase (APX), catalase (CAT), guaiacol peroxidase (GPX), superoxide dismutase (SOD) activities were determined on the 6th, 7th, 8th, and 9th days of drought stress. On the 8th day, the APX activity in the Drought, and Drought+SA groups were observed a higher level, which made up 0.26, and 0.24-fold, respectively. The highest CAT activity was observed in the Drought+SA group and made up 0.14-fold On the 9th day, The GPX activity in the Drough+SA-treated group was 2 times higher than in the other groups. The highest level of SOD activity was 1.8-fold in the Drought+SA group and two times higher than irrigation control. In contrast, SOD activity decreased in the treated groups than Irrigation control (6th day). The results showed that the application of SA was effective on activities of APX, CAT and GPX to determine whether SA may have a role in the regulation of antioxidant defense in plants under drought stress were investigated. Therefore, use of SA can adopted to alleviate drought stress in by wheat growing farmers as a solution to combat climate change.