Regulation of exogenous salicylic Acid on expression of chloroplast gene psbA in wheat (triticum aestivum L.) leaves under heat and high irradiance stress

Wheat leaves were sprayed with salicylic acid (SA) solution of three concentrations (0.1, 0.3, 0.5 mmol·L-1) at grain-filling stage. The expression of chloroplast gene psbA, content of D1 protein and performance of photosystem II (PS II) under heat and high irradiance stress were investigated. The results showed that pretreatment with SA not only retarded inhibition to psbA expression caused by heat and high irradiance stress, but also promoted restoration of psbA expression level after stress under proper temperature and light condition.