EFFECTS OF DROUGHT STRESS ON ANTIOXIDANT ENZYMES IN SEEDLINGS OF DIFFERENT WHEAT GENOTYPES

The aim of this experiment was to study the relationship between the physiological and biochemical indices and drought resistance of different wheat varieties. The response parameters evaluated were: relative water content (RWC), malondialdehyde content (MDA) and isozymes including superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) in seedlings of four genotypes, including Changwu134, Xinong2208, Xinong928 and Shaan253. The wheat seedlings were subjected by -1.0MPa PEG-6000 solution for 1 similar to 6 d in hydroponic condition and the quantities of antioxidant enzymes was measured. The results showed that the expression of SOD isozymes in seedling leaves was strongest in Changwu134 and weakest in Shaan253. CAT isozymes were induced well and increased readily in Changwu134 and Xinong928 seedling leaves than in Xinong2208 and Shaan253 during drought stress. The expression pattern of POD isozymes was similar to CAT. It is well known that SOD, CAT and POD enzymes play a significant role in determining response of wheat genotypes to drought stress. The results of this study suggested that the amount of antioxidant enzymes determine drought stress tolerance in wheat.