Effects of elevated ozone on rice (Oryza sativa L.) leaf lipid peroxidation and antioxidant system.

With rice (Oryza sativa L.) cultivar 3694 Fan as test material, and by using open top chambers, the effects of different ozone (O₃) concentration on the leaf soluble protein content, lipid peroxidation, and antioxidant system were applied. Three treatments were applied, i.e., charcoal-filtered air (CF, 20 nl O₃·L^-1), non-filtered ambient air (NF, 40 nl O₃·L^-1), and elevated O₃ (EO, 75 nl O₃·L^-1). The results showed that there were no significant differences in the test variables between treatments CF and NF. Compared with CF, EO induced a significant decrease of soluble protein content and significant increases of H2O2 and ASA contents and SOD, CAT and POD activities. In treatment EO, the SOD, CAT and POD activities increased by 93.7%, 39.9% and 312.4%, respectively, as compared with treatment CF, while the APX activity tended to increase at first and decrease then. MDA content had no significant differences among the treatments, indicating that leaf antioxidant system could significantly prevent the lipid peroxidation induced by elevated O₃, and rice cultivar 3694 Fan could resist O₃ to some extent. [ABSTRACT FROM AUTHOR]