Bt棉对棉叶螨发生的影响及与次生代谢物质的关系

 为明确Bt棉对棉叶螨发生的影响及其与棉株次生代谢物质的关系，以4个Bt棉品种为材料，以不携带Bt基因的常规棉为对照，在大田和温室中调查了棉叶螨的发生趋势，室内观察了棉叶螨的发育历期，测定了不同品种棉花叶片的棉酚和单宁含量，以及取食不同棉花品种的棉叶螨羧酸酯酶的比活力。结果表明，棉叶螨在4个Bt棉品种上的发生显著重于非Bt棉中棉所12，取食4个Bt棉品种的棉叶螨发育历期均明显短于取食中棉所12的棉叶螨的发育历期。4个抗虫棉品种间棉酚和单宁含量虽有差异，但均显著低于中棉所12，而取食中棉所12的棉叶螨的羧酸酯酶比活力也显著低于4个Bt棉品种。Bt棉本身次生代谢物质含量的改变可能影响了棉叶螨的发生。

Effects of Bt Transgenic Cotton on Occurrence of Cotton Spider Mites in Relation to the Secondary Metabolites in Cotton

We sought to determine the effects of Bt transgenic cotton on occurrence of cotton spider mites, and the relationship with the secondary metabolites in cotton plants. Using four Bt cotton varieties and a non-Bt cotton, CCRI 12, as the control, the abundance and developmental duration of cotton spider mites, and also the activity of their carboxylesterase(CarE) were determined, as well as the gossypol and tannin levels in cotton leaves, both in the field and in the greenhouse. Cotton spider mites were more abundant on four Bt cotton varieties than on the common cotton variety CCRI 12. The development period of cotton spider mites fed on four Bt cotton varieties was shorter than on CCRI 12. The gossypol and tannin levels in four Bt cotton varieties were significantly lower than in CCRI 12, although these also varied greatly among the Bt cotton varieties. The activity of CarE in mites fed on CCRI 12 was significantly lower than in those fed on the four Bt varieties. In general it appears that changes in secondary metabolite levels affect the occurrence of cotton spider mites in Bt cotton.