Bt对分月扇舟蛾体毒性及体内保护酶系影响

Effect of Bacillus thuringiensis on Activities of Protective Enzymes in Clostera anastomosis

以分月扇舟蛾5龄幼虫为研究对象,采用叶片药膜法测定了Bt对其毒性,研究了致死剂量的Bt对其体内SOD、CAT、POD保护酶活性的影响。结果表明:Bt对分月扇舟蛾36、48、72 h的LC30和LC50分别为:24.674、8.578、5.622 ng·L-1和78.311、17.252、11.741 ng·L-1。9 ng·L-1的Bt对分月扇舟蛾幼虫体内的SOD、CAT、POD酶活性均有不同程度的激活作用。17 ng·L-1的Bt处理后,幼虫SOD呈现先升高后降低的趋势,在48 h时达到最大值,为对照的1.704倍;CAT酶活性都略高于对照但变化平缓,仅在处理24 h后,有差异显著性(p<0.01);POD酶活性呈现上升趋势,在处理48、72 h时表现出差异极显著(p<0.01)。不同质量浓度Bt处理后,分月扇舟蛾幼体内的3种保护酶表现出不同的增降趋势,破坏了3种酶的平衡关系,导致细胞内自由基水平过高对虫体产生了不可恢复的毒害作用。

A test was conducted to study the toxic effect of Bacillus thuringiensis （Bt） on the 5 th instar larvae of Clostera anastomosis and the effect of lethal dose of Bt on the activities of protective enzymes in C. anastomosis by leaf membrane. Results showed that LC30 and LC50 of Bt against C. anastomosis at 36 h, 48 h, 72 h were 24. 674, 8. 578, 5. 622 ng · L-1, and 78. 311, 17. 252, 11. 741 ng · L-1 respectively. The activities of SOD, CAT and POD in the larvae treated with 9 ng · L-1 of Bt were activated to varying degrees. After treated with 17 ng · L-1 of Bt, SOD activity of the larvae increased first and then decreased, and SOD activity reached its maximum at 48 h, which was 0. 704 times higher than that of the control; CAT activity was slightly higher than that of the control, and a significant difference was only observed at 24 h （ P〈0.01 ） ; POD activity showed a rising trend and significant differences were found between 48 h and 72 h （P〈0.01）. Different concentrations of Bt destroyed the balance in activities of protective enzymes in the larvae of C. anastomosis, and high levels of free radicals resulted in an irreversible toxic effect on the larvae.