中文摘要：

探索新型多烯大环内酯抗生素农抗702对水稻病原真菌的防病作用机理。在水稻4-5叶期分别喷施5种不同浓度的农抗702，以喷施浓度为125ug／mL的井冈霉素药液为阳性对照，以蒸馏水为阴性对照。喷施后分别取0、1、3、5、7、9d水稻叶片进行5种防御酶的提取和活性测定。结果表明，分别喷施浓度为75、100、125、150、175ug／mL的农抗702和浓度为125ug／mL的井冈霉素药液．其水稻叶片内SOD、POD、PPO、CAT和PAL等5种防御酶活显著高于阴性对照；在0～9d，喷施浓度为125ug/mL的农抗702水稻叶片的5种酶活性达到或超过浓度为125ug／mL井冈霉素喷施效果。可见，农抗702能诱导水稻植株的抗病性。本结果为进一步深入研究农抗702对水稻病原真菌的防病抗病作用机理提供了理论参考。

英文摘要：

To explore the mechanism of defense and resistive ability of a new polyene macrilide antibioticsagricultural antibiotic 702 on rice pathogenic fungi. We spray five different concentrations of agricultural antibiotic 702 on the booting rice with four or five leaves, at the same time, we used the concentration of jinggangmycin is 125 ug/mL as positive comparison and water as negative comparison. After 0, 1, 3, 5, 7, 9 days, we picked the rice leaves and extracted its five defense enzymes and determined their activities. The activities of SOD, POD, PPO, CAT, PAL in rice leaves after we spray a series of concentrations （75, 100, 125, 150 and 175 ug/mL ） of agricuhural antibiotic 702 and the 125 ug/mLfingangmycin were significantly higher than blank control. The five defense enzymes of rice deal with the agricultural antibiotic 702 （125 ug/mL） reached and exceed the treatment with 125 ug/mLjingangrnycin. Agricultural antibiotic 702 can induce the rice get the systemic acquired sistanee. The result of this experiment was useful for the further research of disease prevent mechanism of agricultural antibiotic 702.