Effects of antioxidant enzymes of ascorbate-glutathione cycle in soybean (Glycine max) leaves exposed to ozone

摘要

Open-top chambers (OTCs) were used to investigate the mechanism of antioxidant enzymes to eliminate reactive oxygen species (ROS) of plants under troposphere O_3 stress. The results indicated that, compared to control, the O_3 concentration of 80±10 nL·L~(-1) and 110±10 nL·L~(-1) induced an increase on malondialdehyde (MDA) content and a decrease on superoxide anion (O_2) production rate and hydrogen peroxide (H_2O_2) content during the whole growth stage. Simultaneity, it showed a trend of increasing in earlier stage and decreasing in later stage of the activities of ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR) and glutathione reductase (GR), while the dehydroascorbate reductase (DHAR) activity was increased in earlier period, decreased in middle periods and then increased in later period compared to control, respectively. The results show that elevated O_3 concentration accelerates ROS metabolism rates, reduces the efficiency of antioxidant enzymes that can not tolerate oxidative damage caused by elevated O_3 concentration, which represents injured affects to soybean.