[Objective] Effects of host plants on the activities of some detoxification enzymes and protective enzymes in the meadow moth were explored to provide the basis for studying the physiological mechanisms of the meadow moth, Loxostege sticticalis, to different plants. [Method]In our experiments, the temporal variation of the activities of 3 detoxification enzymes (carboxylesterase, acetylcholinesterase and glutathione-s-transferase) and 3 protective enzymes (superoxide dismutase, peroxidase and catalase) in the midgut of the moths fed with different plants, including lambsquarters, soybean, corn and potato, was tested. [ResultjThe results indicated that the enzyme activity was significantly affected by different host plants. The detoxification enzyme activity in the moths fed with suitable hosts was higher than those fed with unsuitable ones. However, with the feeding time prolonged, the fast-growing enzyme activity in the moths feeding on non-suitable host plants reduced the difference a-mong the moths feeding on different host plants. And the variation trend of protective enzymes was similar to that of the detoxification enzymes. [Conclusion]The results indicated that the variation of the detoxification enzymes and protective enzymes to different plants is the reason why the larvae are adapted to non-suitable host plants.%[目的]探讨寄主植物对草地螟中肠解毒酶及保护性酶活性的影响,为研究草地螟对不同寄主植物的生理适应机制奠定基础.[方法]测定草地螟幼虫取食藜、大豆、向日葵、玉米和马铃薯等5种不同寄主植物后中肠解毒酶羧酸酯酶、谷胱甘肽S转移酶、乙酰胆碱酯酶和保护酶超氧化物歧化酶、过氧化氢酶、过氧化物酶活力的时序变化.[结果]取食不同寄主植物会显著影响幼虫中肠解毒酶活性.取食适宜寄主植物时幼虫中肠解毒酶活力在初期明显高于取食非适宜寄主植物的,但随着取食时间的延长,取食非适宜寄主植物的酶活力快速增长.取食初期,取食不同寄主植物对于中肠保护酶活性也有一定影响,但随着取食时间的延长,保护酶活力基本趋于一致.[结论]试验结果表明,草地螟老龄幼虫中肠解毒酶和保护酶对不同寄主的适应性反应是其取食非适宜寄主能够存活的生理机制之一.
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