中文摘要：

【目的】研究牵牛子石油醚提取物中流分8对朱砂叶螨生物活性的作用机理。[方法]采用玻片浸渍法和叶片残毒法测定了流分8对朱砂叶螨成螨和卵的室内毒力，并采用生化方法测定了谷胱甘肽-S-转移酶、乙酰胆碱酯酶、单胺氧化酶、Ca^2＋-ATP酶活性的影响，通过透射电镜观察流分8对螨体内亚显微结构的破坏。[结果]流分8对朱砂叶螨成螨和卵均有很强的生物活性，对成螨和卵的LC50分别是0．4686mg·ml^-1和1．2212mg·ml^-1，LC50分别是2．5935mg·ml^-1和3．1234mg·ml^-1牵牛子流分8处理朱砂叶螨后，螨体内解毒酶谷胱甘肤-S-转移酶被激活，这说明流分8中存在对朱砂叶螨有毒的物质；而乙酰胆碱酯酶、单胺氧化酶、Ca^2＋-ATP酶均受到不同程度的抑制，这可能引起神经传递的阻断，从而导致螨体的死亡。透射电镜下可见，流分8对螨体内表皮结构、肌纤维、细胞核膜、线粒体、内质网等均有不同程度的破坏。【结论】牵牛子可以有效杀死朱砂叶螨，作为新型植物源农药具有一定的开好价倌

英文摘要：

[ Objective ] The activity of fraction 8 from the petroleum ether extract of Pharbitis purpurea seeds was investigated against Tetranychus cinnabarinus. [ Method ] The acaricidic activity of fraction 8 was measured with the methods of slide dip and leaf residue, and several enzymes in T. cinnabarinus treated with isolation fraction 8 were examined. The ultrastructure of the treated mites was observed by using transmission electron microscope （TEM）. [ Result] The tested fraction showed lethal effects on the mite adults and eggs with the LC50s of 0.4686 and 1.2212 mg/ml and the LC90s of 2.5935 and 3.1234 mg/ml, respectively. Glutathione-S-transferase activity was strongly induced in treated mites whereas acetylcholinease, monoamine oxidase and Ca^2＋-ATPase were suppressed in activity after treatment. The results indicated that the extracted fraction of P purpurea seeds was acaricidal, perhaps attributing to neural transmit block in treated mites. TEM observations revealed that the treated mites suffered from the ruptures of cuticle, muscular filament, nuclear membrane, mitochondria and endoplasmic reticulum. [Conclusion] Thus, P purpurea seeds can be exploited as new resources for developing potential acaricides.