Pinto Delia M, Blande James D, Nykänen Riikka, Dong Wen-Xia, Nerg Anne-Marja, Holopainen Jarmo K
Department of Environmental Science, University of Kuopio, P.O. Box 1627, 70211, Kuopio, Finland.
J Chem Ecol. 2007 Apr;33(4):683-94. doi: 10.1007/s10886-007-9255-8. Epub 2007 Feb 28.
Inducible terpenes and lipoxygenase pathway products, e.g., green-leaf volatiles (GLVs), are emitted by plants in response to herbivory. They are used by carnivorous arthropods to locate prey. These compounds are highly reactive with atmospheric pollutants. We hypothesized that elevated ozone (O(3)) may affect chemical communication between plants and natural enemies of herbivores by degrading signal compounds. In this study, we have used two tritrophic systems (Brassica oleracea-Plutella xylostella-Cotesia plutellae and Phaseolus lunatus-Tetranychus urticae-Phytoseiulus persimilis) to show that exposure of plants to moderately enhanced atmospheric O(3) levels (60 and 120 nl l(-1)) results in complete degradation of most herbivore-induced terpenes and GLVs, which is congruent with our hypothesis. However, orientation behavior of natural enemies was not disrupted by O(3) exposure in either tritrophic system. Other herbivore-induced volatiles, such as benzyl cyanide, a nitrile in cabbage, and methyl salicylate in lima bean, were not significantly reduced in reactions with O(3). We suggest that more atmospherically stable herbivore-induced volatile compounds can provide important long-distance plant-carnivore signals and may be used by natural enemies of herbivores to orientate in O(3)-polluted environments.
植物在遭受食草动物侵害时会释放出可诱导的萜类化合物和脂氧合酶途径产物，例如绿叶挥发物（GLVs）。肉食性节肢动物利用这些物质来定位猎物。这些化合物与大气污染物具有高度反应性。我们推测，臭氧（O₃）浓度升高可能会通过降解信号化合物来影响植物与食草动物天敌之间的化学通讯。在本研究中，我们使用了两个三营养级系统（甘蓝 - 小菜蛾 - 小菜蛾绒茧蜂和菜豆 - 二斑叶螨 - 智利小植绥螨）来表明，将植物暴露于适度升高的大气O₃水平（60和120 nl l⁻¹）会导致大多数食草动物诱导的萜类化合物和GLVs完全降解，这与我们的假设一致。然而，在这两个三营养级系统中，O₃暴露均未破坏天敌的定向行为。其他食草动物诱导的挥发物，如甘蓝中的苄腈和利马豆中的水杨酸甲酯，在与O₃反应时并未显著减少。我们认为，更多在大气中稳定的食草动物诱导的挥发性化合物可以提供重要的长距离植物 - 食肉动物信号，并且可能被食草动物的天敌用于在O₃污染环境中进行定向。
