Response of the antioxidant system to water stress in different wheat varieties

In this study,the concentration or activity changes of some drought indicators,including proline(Pro),soluble sugar,malondialdehyde(MDA),superoxide dismutase(SOD),catalase(CAT)and superoxidase(POD)were measured with two wheat varietiesYongliang 4andXihan 2under water deficit stress.The contents of Pro and MDA increased and the soluble sugar content rose initially and then fell with increased degree and duration of water stress.The MDA content in Yongliang 4increased more than that in Xihan2.The activities of SOD,CAT and POD increased under mild water stress,and activities of these enzymes inXihan 2increased more than those inYongliang 4.However,the activities of the three enzymes rose initially and then decreased under moderate water stress.All the indicators showed differing recovery patterns after rehydration,and compared with Yongliang 4,the overall drought resistance and recovery response ofXihan 2was better.The degree of change of the above stress indictors was ranked:leafsheathstem,showing that the most sensitive organ to water stress was the leaf,and the least sensitive was the stem.