研究经2 mg·mL-1薄荷活性成分处理后朱砂叶螨的症状表现和处理24 h后的透射电镜亚细胞结构,采用生化方法测定薄荷活性成分对朱砂叶螨体内的单胺氧化酶(MAO)、谷胱甘肽-S-转移酶(GSTs)、乙酰胆碱酯酶(AchE)和蛋白酶活性的影响.结果表明:薄荷提取物处理朱砂叶螨后,成螨经历了静止、活跃、痉挛和死亡4个时期.与对照组相比,处理后螨体内MAO活性增强,12h和24 h时活性差异显著(P＜0.05); GSTS亦被激活,24 h内酶活性呈上升趋势；AchE活性受抑制,处理后12h时酶活性最低,处理组与对照组酶活性24 h内变化趋势相同；蛋白酶活性整体处于被抑制状态.薄荷提取物对朱砂叶螨有毒害作用,并引起了螨体内GSTs的解毒,来维持正常的生理功能.AchE的活力受到一定程度的抑制并可能造成神经递质积累、传递阻断.MAO活性被激活,单胺在螨体内没有积累,因而并非通过此途径导致成螨死亡.蛋白酶活性受到抑制表明该物质对消化系统有破坏.透射电镜观察发现对照组颈部体壁亚细胞结构完整且规律,而处理组结构完全溶解,无法辨认.初步推测薄荷提取物通过破坏神经系统及消化系统,对朱砂叶螨产生毒害作用.薄荷提取物可以作为新型植物源农药,且具有一定的开发价值.%In order to investigate the mechanism of acaricidal activity of Mentha piperita extracts against Tetranychus cinnabarinus, adult spider mites were treated with 2 mg . mL-1 eluted fraction V of M. Piperita extracts in vitro, and the resulting acaricidal symptom and ultrastructure were observed. Furthermore, the enzyme activity of monoamine oxidase ( MAO) , glutathione-S-transferase ( GSTs) , acetylcholine esterase ( AchE ) and proteinase in the treated mites was examined. The results illustrated that the toxic symptom of the treated mites experienced four different phases, namely quiescence, activity, convulsion and death. The ultrastructural observation by the electronic microscope indicated that the control had an intact subcellular structure, while the treated mites were severely damaged and their subcellular structure was hardly identified. The enzyme activities of spider mites varied after being treated with M. Piperita extracts. MAO activity was boosted up, especially at the 12th and 24th h after treatment (P < 0. 05). The GSTs activity was intrigued after treatment and exhibited an increasing trend during 4-24 h, suggesting that the poisonous component accumulated in T. Cinnabarinus and mobilized GSTs for the detoxification. Meantime, the AchE and proteinase activity were inhibited by M. Piperita extracts. It suggested that the transfer of nerve impulse was possibly interdicted and the digestive system was maladjustedd.
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