Herbivore-induced plant volatiles induce an indirect defence in neighbouring plants
Herbivore-induced plant volatiles induce an indirect defence in neighbouring plants
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DOI：
10.1111/j.1365-2745.2006.01120.x
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发表时间：
2006-05-01
影响因子：
5.5
通讯作者：
Heil, M
中科院分区：
文献类型：
--
作者：
Kost, C;Heil, M
许多植物物种对草食动物的反应是增加挥发性有机化合物（VOC）的排放：这些化合物吸引食肉节肢动物，从而起到间接防御机制的作用。邻近的植物是否能够“窃听”这种空气传播的信号，并相应地调整它们的防御，仍然存在争议。（Phaseolus lunatus）研究食草动物诱导的VOC是否诱导另一种间接防御策略，即在同种植物邻居中分泌花外花蜜（EFN），以及在自然条件下，这是否增强了接受植物的防御状态。EFN的分泌是由草食动物释放的VOC诱导的，受损的豆卷须以及类似于天然的合成VOC混合物。一个长期的实验比较了EFN单独的防御效应和VOC介导的防御效应（EFN诱导加上植物防御者的吸引），结果表明利马豆受益于两种间接防御。用挥发性有机化合物的人工混合物或EFN重复处理卷须，导致捕食性和寄生性昆虫的累积数量增加（即蚂蚁和黄蜂），以及减少草食动物的损害和增加花序和叶子的产量。我们的研究结果表明，一种间接防御机制可以诱导同种植物的另一种，并且利马豆植物可以在自然条件下受益于这种VOC诱导的EFN分泌。花外蜜腺和植食性时释放挥发性有机化合物的能力都存在于许多植物类群中，因此，空气传播的信号可能代表了一种常见的机制，用于调节EFN在植物部位的分泌，这些植物部位面临着植食性增加的风险。
Many plant species respond to herbivory with increased emission of volatile organic compounds (VOCs): these attract carnivorous arthropods and thereby function as an indirect defence mechanism. Whether neighbouring plants can 'eavesdrop' on such airborne cues and tailor their defences accordingly, remains controversial.We used Lima bean plants (Phaseolus lunatus) to investigate whether herbivore-induced VOCs induce another indirect defence strategy, i.e. the secretion of extrafloral nectar (EFN) in conspecific plant neighbours, and whether this enhances the defence status of the receiving plant under natural conditions.EFN secretion was induced by VOCs released from herbivore-damaged bean tendrils as well as by a synthetic VOC mixture resembling the natural one. One constituent of the herbivore-induced blend - the green leaf volatile (3Z)-hex-3-enyl acetate - was sufficient to elicit the defence reaction.A long-term experiment comparing the defensive effect of EFN alone with the VOC-mediated effect (EFN induction plus attraction of plant defenders) suggested that Lima bean benefits from both indirect defences. Repeated treatment of tendrils with either an artificial blend of VOCs or with EFN led to the attraction of a higher cumulative number of predatory and parasitoid insects (i.e. ants and wasps) as well as to less herbivore damage and an increased production of inflorescences and leaves.Our results demonstrate that one indirect defence mechanism can induce another one in conspecific plants, and that Lima bean plants can benefit from this VOC-induced EFN secretion under natural conditions. Both extrafloral nectaries and the capability to release VOCs upon herbivory are present in many plant taxa and airborne signalling may thus represent a common mechanism for regulating the secretion of EFN in plant parts which face an increased risk of herbivory.