SO2-caused oxidative stress and modulation of some signal molecules in wheat
二氧化硫对小麦的氧化胁迫及其某些信号分子的调节

By adding different concentration SO2 to culture boxes, this paper studied the responses of wheat seedling's superoxide anion radical O2*- and antioxidant enzymes to SO2. The results showed that when the concentration of SO2 was 10 and 40 microl x L(-1), the O2*- content and peroxidase (POD) and catalase(CAT) activities of wheat leaf were increased, while the activity of superoxide dismutase(SOD) was reduced. When the SO2 concentration was 50 microl x L(-1), the activities of POD and CAT were decreased, with the top end leaves appeared necrosis, and more fungi multiplied on green leaves. Presoaking wheat seeds with 1 mmol x L(-1) salicylic acid (SA) for 6 h or with 10 mmol x L(-1) H2O2 for 12 h could efficiently alleviate the oxidative stress caused by SO2, with the O2*- content decreased and the activities of test antioxidant enzymes increased. Under SO2 fumigation, ethylene significantly inhibited the activities of test enzymes, and promoted the O2*- production rate. When applying SA and ethylene at the same time, SA could almost completely eliminate the influences of ethylene on O2*- production and test enzyme activities.