Effects of Fenvalerate on the Activities of Antioxidant Enzymes,and Contents of Malondiadehyde (MDA) in Pakchoi

In order to study the pyrethroids pesticides stress on the physiological and biochemical process of vegetables, effects of different concentrions of fenvalerate stress(20% emulsifiable concentrate, recommended dose: 1500 times dilution; double dose: 750 times dilution)on the activities of antioxidant enzymes, and contents of malondiadehyde(MDA)in pakchoi were investigated under the open-field condition. Results showed that effects of fenvalerate stress on the activities of antioxidant enzymes were different, whether the recommended dose or double dose. After spaying pesticide, superoxide dismutase(SOD)activity in pakchoi was inhibited in 3d, and then increased, on the 21st day it was inhibited again. Catalase(CAT)activity was slightly increased, and reached to the control level on the 21st day, but the activity of peroxidase(POD)was evidently inhibited in pakchoi. Fenvalerate with different concentrations could increase content of MDA in pakchoi. The content of MDA increased with the increase of concentrations of fenvalerate, and there was a certain dose-response relationship between them. So fenvalerate stress could promote the lipid peroxidation of pakchoi. Fenvalerate could cause certain oxidative damage on pakchoi, and cause SOD, CAT, POD activities change in different degrees. Fenvalerate stress had larger impact on the activities of SOD and POD, and the content of MDA. Among them the impact on MDA content was the greatest. So the content of MDA could be used as the marker under the stress of fenvalerate on the plants.