极端高温对木薯单爪螨保护酶活性的影响研究

Effect of Extreme High Temperature on the Enzymes of Cassava Green Mite Mononychellus tanajioa(Acari:Tetranychidae)

为探讨木薯单爪螨的生态适应性机理,揭示其种群扩散蔓延机制。开展了极端高温胁迫对木薯单爪螨各龄螨的存活率及几种保护酶(多酚氧化酶(PPO)、过氧化物酶(POD)、抗坏血酸过氧化物(AsA-POD)、过氧化氢酶(CAT)和超氧化物歧化酶(SOD))活性的影响研究。结果表明:经42℃高温处理,木薯单爪螨各龄螨最多仅可存活66h,不能进一步发育。PPO和CAT活性在幼螨体内显著下降,而在前若螨到成螨却显著升高,而尤以前若螨升高最高;与对照相比,AsA-POD活性在幼螨体内无变化,但在前若螨体内可升高达对照的3.286倍,到后若螨期升高至对照的1.923倍,成螨期无显著变化;各龄螨体内POD和SOD的活性均无显著变化。因此,说明PPO、CAT和AsA-POD活性变化可能在木薯单爪螨抵抗高温过程中具有重要作用。

Temperature was one of the important ecological factors for development and reproduction of Mononychellus tanajioa.In order to learn about the ecological adaptation of M.tanajoa after its invasion into our country and provide a foundation for the monitoring early warning and effective prevention as well as analyze its invasion,diffusion and ecological adaptation mechanism,this study researched the effect of extremely high-temperature（42℃） treatment on the survive and the activity changes of several protective enzymes [polyphenol oxidase（PPO）,peroxidase（POD）,ascorbate oxidase（AsA-POD）,catalase（CAT） and superoxide dismutase（SOD）] by spectrophotometric endpoint assay after the mites in each growth period were treated for different lengths of time at 42℃.The results showed that 42℃ had important effect on the protective enzymes of M.tanajioa.Activities of PPO and CAT of larvae significantly decreased under 42℃ treatment,but that of them were increased in protonymphs and adults,especially in protonymphs.In 42℃,AsA-POD activities of larvae and adults had no changes,but that increased 3.286-fold in protonymphs and 1.923-fold in deutonymph relative to that in 25℃.High temperature of 42℃ had no effect on POD and SOD activities of M.tanajioa.These results suggested that the tolerance of M.tanajioa to high temperature could be associated with PPO,CAT and AsA-POD,but not with POD and SOD activities.