Heil Martin, Silva Bueno Juan Carlos
Fachbereich 9, Allgemeine Botanik/Pflanzenökologie, Universität Duisburg-Essen, Universitätstrasse 5, D-45117 Essen, Germany.
Proc Natl Acad Sci U S A. 2007 Mar 27;104(13):5467-72. doi: 10.1073/pnas.0610266104. Epub 2007 Mar 7.
Plants respond to herbivore attack with the release of volatile organic compounds (VOCs), which can attract predatory arthropods and/or repel herbivores and thus serve as a means of defense against herbivores. Such VOCs might also be perceived by neighboring plants to adjust their defensive phenotype according to the present risk of attack. We exposed lima bean plants at their natural growing site to volatiles of beetle-damaged conspecific shoots. This reduced herbivore damage and increased the growth rate of the exposed plants. To investigate whether VOCs also can serve in signaling processes within the same individual plant we focused on undamaged "receiver" leaves that were either exposed or not exposed to VOCs released by induced "emitter" leaves. Extrafloral nectar secretion by receiver leaves increased when they were exposed to VOCs of induced emitters of neighboring plants or of the same shoot, yet not when VOCs were removed from the system. Extrafloral nectar attracts predatory arthropods and represents an induced defense mechanism. The volatiles also primed extrafloral nectar secretion to show an augmented response to subsequent damage. Herbivore-induced VOCs elicit a defensive response in undamaged plants (or parts of plants) under natural conditions, and they function as external signal for within-plant communication, thus serving also a physiological role in the systemic response of a plant to local damage.
植物通过释放挥发性有机化合物（VOCs）来应对食草动物的攻击，这些挥发性有机化合物可以吸引捕食性节肢动物和/或驱赶食草动物，从而作为抵御食草动物的一种防御手段。相邻植物也可能感知到这些挥发性有机化合物，以便根据当前的攻击风险调整自身的防御表型。我们将利马豆植株在其自然生长地暴露于受甲虫损伤的同种枝条释放的挥发性物质中。这减少了食草动物造成的损害，并提高了暴露植株的生长速率。为了研究挥发性有机化合物是否也能在同一植株内的信号传导过程中发挥作用，我们将重点放在未受损的“接收”叶片上，这些叶片要么暴露于由诱导的“释放”叶片释放的挥发性有机化合物中，要么未暴露于其中。当接收叶片暴露于相邻植株或同一枝条的诱导释放者释放的挥发性有机化合物时，其花外蜜分泌增加，但当挥发性有机化合物从系统中去除时则不然。花外蜜吸引捕食性节肢动物，代表一种诱导防御机制。这些挥发性物质还引发花外蜜分泌，使其对后续损伤表现出增强的反应。在自然条件下，食草动物诱导的挥发性有机化合物在未受损的植株（或植株部分）中引发防御反应，它们作为植株内通讯的外部信号，因此在植物对局部损伤的系统反应中也发挥着生理作用。
