增效醚(PBO)对棉铃虫细胞色素P450的抑制作用及对拟除虫菊酯的增效作用

Inhibition of cytochrome P450 in Helicoverpa armigera (Hübner) by piperonyl butoxide (PBO) and its synergism to pyrethroids

在增效醚 (PBO)对棉铃虫Helicoverpaarmigera 3龄幼虫处理后的不同时段 ,细胞色素P45 0的含量受到不同程度的抑制 :在处理后 1h ,细胞色素P45 0的含量仅为对照的 43 9% ,至处理后 12h ,细胞色素P45 0的含量下降到最低点 ,仅为对照的 2 3 4% ;而处理后 18～ 2 4h ,细胞色素P45 0被抑制的程度有所减弱 ,其含量分别为对照的 85 8%和 70 0 %。生物测定结果表明 ,PBO对所测定的 7种拟除虫菊酯均有不同程度的增效作用 ,对氰戊菊酯的增效比最高 (119 3) ,对氯菊酯的增效比最低 (2 1)。由于细胞色素P45 0是拟除虫菊酯的重要解毒酶系 ,PBO的处理可使棉铃虫细胞色素P45 0的含量大幅度下降 ,使其对杀虫剂的解毒能力减弱 。

Treatment in vivo with PBO caused apparent reduction of the cytochrome P450 level in third instar larva of Helicoverpa armigera. At 1 hour after PBO treatment, the content of cytochrome P450 was only 43 9% of that in the control. At 12 hours after PBO treatment, the content of cytochrome P450 decreased to 23 4% of the control. While 18 and 24 hours after treatment, the content of cytochrome P450 was 85 8% and 70 0% of the control respectively. The bioassay results indicated that PBO synergised 7 pyrethroids significantly, with the highest synergistic ratio (119 3) for fenvalerate and the lowest (2 1) for permethrin. Because the cytochrome P450 is an important detoxifying enzyme, the reduction of the cytochrome P450 level can impede the oxidative metabolism and cause obvious synergism to pyrethroids in H.armigera.