植物次生物质对烟青虫和棉铃虫食物利用及中肠解毒酶活性的影响

Effects of plant allelochemicals on nutritional utilization and detoxication enzyme activities in two Helicoverpa species

用分别添加 0 5 % (干重比 )棉酚、烟碱、番茄苷和辣椒素 4种植物次生物质的人工饲料饲养烟青虫Helicoverpaassul ta和棉铃虫H .armigera 5龄幼虫 48h ,测定这些次生物质对烟青虫和棉铃虫的营养效应和中肠谷胱甘肽S 转移酶 (GST)及羧酸酯酶 (CarE)活性的影响。结果表明 :在实验浓度下 ,棉酚可显著降低烟青虫的相对消化率 ,但对棉铃虫却有助食作用 ;番茄苷抑制烟青虫的取食和生长 ,对其近似消化率和食物利用率也有显著的抑制作用 ,但食物转化率有明显升高 ,对棉铃虫的各营养指标无显著影响 ;烟碱对烟青虫和棉铃虫的相对生长率均无影响 ;辣椒素使烟青虫的取食量有大幅度的提高 ,对棉铃虫的取食量无影响 ,但引起其相对消化率的提高。由此可见 ,棉铃虫对 4种次生物质有普遍的适应性 ,而烟青虫只对寄主植物所含的烟碱和辣椒素有较好的适应性。烟青虫和棉铃虫幼虫中肠CarE活性不受 4种次生物质的影响 ,烟碱和辣椒素对烟青虫GST有显著的诱导作用 ,番茄苷对烟青虫GST活性则有抑制作用 ,4种次生物质对棉铃虫GST均无显著影响。

The effects of four plant allelochemicals,gossypol, nicotine, tomatine and capsicine, on nutritional utilization and detoxication enzymes activities in midgut were investigated with the 5th instar larvae of cotton bollworm, Helicoverpa armigera, and oriental tobacco budworm, H. assulta. The results showed that H. armigera exhibited wide adaptability to all the four allelochemicals, whereas H. assulta could only fit well to nicotine and capsicin, which were the allelochemicals from its host plants. Midgut CarE activity was unaffected by the allelochemicals in H. armigera and H. assulta. GST activity in the midgut of H. assulta could be strongly induced by nicotine and capsicine, but significantly inhibited by tomatine; none of the four allelochemicals could affect midgut GST activity in H. armigera.