中文摘要：

植物在受植食性昆虫为害时能产生防御反应,并且植物的茉莉酸信号转导途径在这一过程中发挥着重要作用。然而,迄今为止对于油菜Brassica campestris的诱导防御反应很少有研究报道。为此,本实验通过测定油菜内茉莉酸和胰蛋白酶抑制剂含量研究了油菜在斜纹夜蛾Spodoptera litura幼虫为害后的抗虫性和胰蛋白酶抑制剂含量的变化,并分析这些变化在油菜诱导抗虫性与茉莉酸信号转导途径中的关系。结果表明：斜纹夜蛾幼虫取食能导致油菜体内茉莉酸和胰蛋白酶抑制剂含量系统性上升,外用茉莉酸甲酯处理也能系统性增加油菜的胰蛋白酶抑制剂含量,并且取食茉莉酸甲酯处理或斜纹夜蛾幼虫取食过的叶片能显著降低斜纹夜蛾幼虫的体重,两者的体重分别为对照植株上的67.5%和60.2%。机械损伤加斜纹夜蛾幼虫口腔分泌物处理能引起处理叶中茉莉酸和胰蛋白酶抑制剂含量的增加,但其诱导效果与机械损伤加水没有显著差异,并且两者明显低于虫害的诱导效果,两种处理的茉莉酸和胰蛋白酶抑制剂含量分别为虫害诱导的68.4%和24.4%及62.9%和36.9%;多次连续机械损伤的诱导效果与一次损伤的没有明显差异。结果说明斜纹夜蛾幼虫诱导的油菜抗虫性与茉莉酸信号转导途径有关,而其激活油菜抗虫反应的机理则可能与其特定的取食行为相关。

英文摘要：

When attacked by herbivores,plants produce defense responses,and the jasmonic acid（JA）signaling pathway plays an important role in this process.So far,however,little was known about the herbivore-induced defense responses in Chinese cabbage（Brassica campestris L.）.Therefore,the defense responses of B.campestris attacked by Spodoptera litura（Fabricius）and their relations to the JA signaling pathway were studied through assaying the contents of JA and trypsin protease inhibitors（TrypPIs）in B.campestris plants.The results showed that infestation by S.litura resulted in systemic increases in levels of both JA and TrypPIs in B.campestris plants,of which the level of TrypPIs could also be systemically induced by exogenous application of methyl jasmonate（MeJA）.Moreover,body weights of S.litura caterpillars fed on leaves treated by MeJA or infested by the herbivore decreased significantly,only 67.5% and 60.2% of that fed on control leaves,respectively.Treatment with wounding plus the caterpillar oral spit（OS）could cause the increase in JA and TrypPIs level in the treated leaves,but its induction efficacy was similar to that induced by wounding plus water（W）and far lower than that induced by the herbivore infestation.The levels of JA and TrypPIs in OS-or W-treated plants were 68.4% and 62.9%,and 22.4% and 36.9% of those in control plants,respectively.We also found that there was no significant difference in the induction efficacy between the treatments ＂wounding once＂ and ＂wounding multiple times＂.The results suggest that the defense responses of B.campestris plants induced by the herbivore are related to the JA signaling pathway,and elicitation of the responses is probably involved in the specific feeding behavior of the herbivore.