Changes in protective enzyme activities in cells of Hemarthria compressa under water stress

Two national varieties Guangyi and Chonggao were used to study the changes of superoxide dismutase(SOD),peroxidase isoenzyme(POD),catalase(CAT)and malondialdehyde(MDA)in roots.The results showed that the MDA content and the activities of superoxide dismutase,peroxidase isoenzyme,and catalase in the roots increased during water stress,with a peak at 14days.After that,the content of malondialdehyde and the activities of the three kinds of protective enzymes declined significantly.The study also showed that the initial rise in the content of malondialdehyde was mainly caused by drought stress.However,the rises in the three kinds of protective enzymes activities may result from the rise of malondialdehyde.After 14days of drought stress,the reduction in content of the three protective enzymes may due to their tolerance and adaptability after experiencing the drought-threshold period.During the study,the roots of Chonggao always had a higher MDA than Guangyi.Based on the drooping and wilting status of the two grasses,we conclude that Guangyi has a greater drought resistance than Chonggao.