Studies on antioxidant system of Astragalus membranaceus after infected with Fusarium oxysporum

In order to study the physiological and biochemical changes of Astragalus membranaceus in the process of root rot,Astragalus membranaceus is induced by being inoculated with Fusarium oxysporum artificially under the experimental conditions,and the changes of 5 indixes including peroxidase(POD),catalase(CAT),superoxide dismutase(SOD),soluble protein and malondialdehyde(MDA) are measured every seven days during the process.The results show that when the healthy Astragalus membranaceus become rotten gradually,the activities of peroxidase(POD),catalase(CAT) and superoxide dismutase(SOD) increased first but decrease afterwards,and the activities of SOD and CAT peak within 7 days while the activity of POD peak within 14 days;the content of malondialdehyde(MDA) peak within 14 days and gradually decrease when the time for treating is prolonged;and the tendency of the content of soluble protain is similar to that of the content of malondialdehyde(MDA).