中文摘要：

为探明苍耳活性组分对害虫拒食作用的机理,研究了苍耳（Xanthium sibiricum）甲醇提取物的氯仿萃取物对粘虫（Pseudaletia separataWalker）的拒食活性及其中肠消化酶和血淋巴酯酶活性的影响.结果显示,苍耳氯仿萃取物对粘虫四龄幼虫的选择性拒食中浓度（AFC50）为0.038 g/mL.0.01 g/mL浓度的苍耳氯仿萃取物处理的玉米叶喂食粘虫四龄幼虫,喂食后12 h,粘虫中肠蛋白酶、淀粉酶和羧酸酯酶活性均受到明显抑制,血淋巴羧酸酯酶抑制率为49.2%;喂食后24 h,粘虫中肠蛋白酶和淀粉酶受到的抑制率高达67.9%和58.3%,中肠羧酸酯酶也受到明显抑制,而血淋巴羧酸酯酶活性则增加.

英文摘要：

The antifeedant effect and enzyme activity of extract from Xanthium sibiricum on Pseudaletia separate are investigated.The results show that the selective antifeedant concentration rate（AFC50） of chloroform extract from Xanthium sibiricum to Pseudaletia separata 4th larvae is 0.038 g/mL.In experimental session,the intestinal protease,amylase and esterase activity are distinctly inhibited by the test extract,and the carboxylesterase specific activity of haemolymph also reduced with inhibition rate of 49.2%,12 h after treatment.However,24 h after treatment,the intestinal protease and amylase of Pseudaletia separata 4th larvae are highly inhibited with the rate of 67.9% and 58.3%,respectively,and the activity of midgut carboxylesterase is also significantly inhibited.Meanwhile,the activity of hemolymph esterase is induced.