Abstract Communication between plants mediated by herbivore-induced volatile organic compounds has been extensively studied aboveground. However, the role of root herbivory in belowground plant-plant communication is much less understood. We here investigated whether root herbivores can trigger plant roots to emit warning signals to neighbouring plants that are not yet in direct contact with them. We used a split-root system and infected half of the roots of Agrostis stolonifera plants with root-knot nematodes (Meloidogyne minor) and left the other half uninfected. As a control, we grew plants without nematodes in separate pots. Leachates from each split-root soil compartment and from soils with control plants were applied to separate pots with A. stolonifera plants, of which biomass allocation and morphological traits were measured one month after leachate addition. Plants receiving leachates from the soil with the nematode-free roots of the nematode-infected plants showed a significantly larger total biomass, more root branches, and deeper rooting than plants receiving leachates from the soil with the nematode-infected roots or from soil with control plants. Plants were taller and the root/shoot ratio was higher in plants receiving leachates from soil with the nematode-free roots than in plants receiving leachates from soil with nematode-infected roots. Shoot tiller number was higher in plants receiving leachates from either root compartment of the nematode-infected plants than in plants receiving control leachates. Our results suggest that an overcompensation response was triggered by systemically induced root-derived compounds from nematode-free roots of a plant locally infected with root-feeding nematodes. Signals from directly attacked roots of the same nematode-infected plant only caused receiver plants to develop more shoot tillers, possibly for future stolon development to grow away from the infected area. This may indicate an anticipatory tolerance response to root feeders that are still distant and an additional generalized escape response to root feeding.

中文翻译：

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线虫感染根系的地下植物-植物信号传导

摘要 由草食动物诱导的挥发性有机化合物介导的植物之间的交流已在地上进行了广泛的研究。然而，根食草在地下植物 - 植物交流中的作用却知之甚少。我们在这里调查了根食草动物是否可以触发植物根部向尚未与它们直接接触的邻近植物发出警告信号。我们使用分根系统并用根结线虫（小根结线虫）感染 Agrostis stolonifera 植物的一半根，而让另一半未感染。作为对照，我们在不同的盆中种植没有线虫的植物。来自每个裂根土壤隔室和来自具有对照植物的土壤的渗滤液被施加到具有 A. stolonifera 植物的不同盆中，其中生物量分配和形态性状在渗滤液加入后1个月进行测量。与从受线虫感染的根部土壤或对照土壤中接受渗滤液的植物相比，接受来自受线虫感染植物的无线虫根系的土壤渗滤液的植物显示出显着更大的总生物量、更多的根分枝和更深的生根植物。接受无线虫根系土壤渗滤液的植物比接受线虫感染根系土壤渗滤液的植物更高，根/茎比也更高。接受线虫感染植物任一根部渗滤液的植物的分蘖数高于接受对照渗滤液的植物。我们的研究结果表明，过度补偿反应是由局部感染食根线虫的植物的无线虫根中系统诱导的根衍生化合物触发的。来自同一线虫感染植物的直接攻击根部的信号只会导致接收植物发育更多的分蘖，可能是为了未来的匍匐茎发育远离感染区域。这可能表明对仍然遥远的根系饲养者的预期耐受反应和对根系进食的额外普遍逃逸反应。可能是为了未来的匍匐生长远离感染区域。这可能表明对仍然遥远的根系饲养者的预期耐受反应和对根系进食的额外普遍逃逸反应。可能是为了未来的匍匐生长远离感染区域。这可能表明对仍然遥远的根系饲养者的预期耐受反应和对根系进食的额外普遍逃逸反应。