Bt转基因棉花抗棉铃虫毒性机理研究

Toxicologcal Activities of Bt Transgenic Cotton Plants on the Cot-ton Bollworm(Helicoverpa armigera)

应用江苏省农业科学院经济作物研究所提供的Ｂｔ转基因棉花（编号８８４０），经盆栽、田间反复鉴定对棉铃虫１龄幼虫抗虫效果平均为９３．１％，叶、蕾、铃饲喂３龄幼虫抗虫效果分别为９０％、８５％、５５％测定毒性机理。棉铃虫３龄幼虫取食抗虫棉２ｄ后，其食量、排泄量分别比该材料未导入Ｂｔ转基因对照植株减少５７．１０％，５７．１９％；幼虫长度、体重增长率分别比对照减少７１．６９％、８１．５１％。４ｄ后食量、排泄量减少７２．０２％、７７．３３％，体长和体重增长率分别比对照减少９３．０２％、１０７．７９％。测定中肠、血清ｐＨ值分别为８．１９和６．４，与对照８．３６、６．５差异不大。中肠超微结构观察，取食抗虫棉中毒死亡的棉铃虫幼虫中肠横纹肌呈收缩状；表明中肠处于中毒痉挛状态，吸收营养物质的柱状细胞微绒毛萎缩并局部被破坏，肠壁细胞质内的细胞器减少。营养物质自耗成空胞。而取食对照植株幼虫中肠超微结构则相反，肌肉舒畅。微绒毛多而正常，细胞器丰富，幼虫生长发育正常。

The bollworm(Helicoverpa armigera Hubner)resistant cotton plants were se-lected from the Bt transgenic cotton crops. The average resistant effect of the plants onthe lst instar larvae was 93.1%。The lethal activities on the 3rd instar larvae raised on thelaef,buds,bolls was 90%,85%and 55%,respectively were studied toxicological activi-ties. The ingestion and rejeetment quantity of the larvae raised on the resistant plants dur-ing the initial 2 days was 57.10%and 57.19%as much as that raised on the non-resisi-tant cotton and the growth rate of body length and weight reduce 71.69%and 81.51%。The pH value in the midgut and hemolymph of treated larvae ahowed no visible variation.The altrostructural observation on the midgut of the toxic larvae showed the constractionof the striated muscle and partially destruction of microvilli and the exhausting of the con-tents in the protoplasm of the columnlar epithelial cells.