The relationship between disease resistance to Xanthomonas oryzae pv. oryzae and peroxidation on membrane lipid induced by paraquat and Tiron was studied. The results showed that pre treatment with PQ induced systematic resistance to strain 76 25, increased the activities of CAT and POD, and MDA content in treated leaves. The changes began from 24 h and were greater during 48 h to 72 h after treatment. On an average, CAT activity increased by 16.5 percent and 11.3 percent, POD activity increased by 37.2 percent and 25.3 percent, MDA content increased by 38.5 percent and 32.2 percent in treated leaves of Yushuinuo and Zhefu 802 , respectively. The saturate fatty acid increased by 11.8 percent and IUFA decreased by 7.5 percent in the leaves of Zhefu 802 treated by PQ . Tiron showed a negative effect on the induced resistance to XOO 76 25 and on the changes above tested items caused by PQ.
