白背飞虱对马拉硫磷和异丙威的抗性机制

测定了白背飞虱不同品系体内与抗药性相关酶系如酯酶、羧酸酯酶、谷膦甘肽S-转移酶和乙酰胆碱酯酶等活性。与敏感品系S相比，抗马拉硫磷品系顺具高水平羧酸酯酶活性。酶反应动力学试验表明，羧跋酯酶的质与量均发生改变；等电聚焦电泳显示与pI5．26～5．84酯酶扩增有关。耐弄丙威品系IT乙酰胆碱酯酶活性相对较低，而药剂对其I50则明显高于S。不同品系的谷胱甘肽S—转移酶活性无显著差弄。作者认为，白背飞虱对马拉硫磷和异丙威产生抗性分别与羧酯酯酶活性增高和乙酰胆碱酯酶对药剂敏感性降低有关。

The resistance mechanisms to malathion and isoprocarb of white-backed planthopper, Sogatella furcifera (Horvath)

The activities of enzymes related to insecticide resistance, i. e. esterase, carboxylesterase, glutathione S-transferase and acetylcholinesterase, in the different strains of white-backed planthopper, Sogatella furcifera were measured. Compared with the susceptible strain (S), malathion-resistant strain (MR) was higher in carboxylesterase activity significantly. The measure of kinetic constants showed that carboxylesterase was changed in both quantity and quality, and the isoelectrofocusing electrophoresis (DEF) also displayed that this was correlated with the amplification of carboxylesterase at pI 5 . 26 - 5. 84. The activity of acetylcholinesterase in isoprocarb-tolerant strain (IT) was lower than that in S strain, but the I50 to acetylcholinesterase of chemicals was markedly higher in IT. There was no significant difference in the activity of glutathione S-transferase among the strains. It was suggested that the resistances to maiathion and isoprocarb of Sogatella Jurcifera were respectively related to the increase of carboxylesterase activity and the decrease of acetylcholinesterase sensitivity.