Effects of O3 on SOD, POD, CAT and H2O2
By comparison, SOD exhibited an increase of activity in wheat, rice and soybean. We only observed significant altered activity of SOD in soybean under O3 treatment (Fig.2A). Compared with CF treatment, elevated [O3] inhibited activities of POD and CAT in wheat and soybean, meanwhile, simulated the activity in rice. POD were reduced in wheat and soybean, but increased by two fold in rice (Fig. 2B). There were no significant changes in activities of CAT in rice and soybean, except wheat (Fig. 2C). Moreover, the concentration of H2O2 in rice and soybean leaves was strongly increased in response to O3-exposure (Fig. 2D). However, there was no significant increase in H2O2 concentration in wheat.