PHYSIOLOGICAL AND MOLECULAR BASIS OF THE EFFECTS OF EXOGENOUS SELENIUM APPLICATION ON WHEAT SEEDLING PERFORMANCE UNDER DROUGHT STRESS

Drought stress is a severe problem for wheat production. The purpose of the present experiment was to study the effects of the exogenous sodium selenite application at different concentrations on wheat seedlings performance under drought stress. Two wheat varieties, 'Shunmai-1718' and 'Jintai-102' were used as materials in this study and four selenium concentration levels were prepared from distilled water (CK), and 20 mg/L (Sel), 40 mg/L (Se2) and 60 mg/L (Se3) of sodium selenite. 7 days after the sowing, the sodium selenite solutions were foliarly applied to wheat seedlings. 9 days after the sowing, 20% PEG-6000 was used to simulate drought conditions for 7 days. The results showed that exogenous selenium significantly increased the plant height, root length, root number, fresh weight and dry weight of wheat seedlings under drought stress. Foliar application of sodium selenite under drought stress also increased antioxidant enzyme activity and the osmoprotectant contents while reducing the content of MDA and O-2(-). Furthermore, the application of sodium selenite under drought stress up-regulated the levels of transcriptional expression in some genes related to antioxidative enzymes and osmo-protectants such as Plant peroxidase, Class III peroxidase, Glutathione S-transferase and Catalase immune-responsive.