Data from: The ecology of herbivore-induced silicon defences in grasses

Silicon as a defence against herbivory in grasses has gained increasing recognition and has now been studied in a wide range of species, at scales from individual plants in pots to plant communities in the field. The impacts of these defences have been assessed on herbivores ranging from insects to rodents to ungulates. Here, we review current knowledge of silicon mediation of plant–herbivore interactions in an ecological context. The production of silicon defences by grasses is affected by both abiotic and biotic factors and by their interactions. Climate, soil type and water availability all influence levels of silicon uptake, as does plant phenology and previous herbivory. The type of defoliation matters and artificial clipping does not appear to have the same impact on silicon defence induction as herbivory which includes the presence of saliva. Induction of silicon defences has been demonstrated to require a threshold level of damage, both in the laboratory and in the field. In recent studies of vole–plant interactions, the patterns of induction were found to be quantitatively similar in glasshouse compared with field experiments, in terms of both the threshold required for induction and timing of the induction response. The impacts of silicon defences differ between different classes of herbivore, possibly reflecting differences in body size, feeding behaviour and digestive physiology. General patterns are hard to discern however, and a greater number of studies on wild mammalian herbivores are required to elucidate these, particularly with an inclusion of major groups for which there are currently no data, one such example being marsupials. We highlight new research areas to address what still remains unclear about the role of silicon as a plant defence, particularly in relation to plant–herbivore interactions in the field, where the effects of grazing on defence induction are harder to measure. We discuss the obstacles inherent in scaling up laboratory work to landscape-scale studies, the most ecologically relevant but most difficult to carry out, which is the next challenge in silicon ecology.禾本科植物利用硅作为植食防御的策略已获得越来越多的认可，目前已在从盆栽个体植株到野外植物群落的多种尺度下，对多个物种开展了相关研究。这类防御措施的影响已在涵盖昆虫、啮齿类乃至有蹄类的各类植食动物中得到评估。本文综述了当前学界在生态学背景下，关于硅介导植物-植食动物互作的相关认知。 禾本科植物硅基防御的合成受到非生物、生物因子及其交互作用的共同调控。气候、土壤类型与水分可利用性均会影响硅的吸收水平，植物物候与既往植食经历同样会产生此类影响。剪叶方式至关重要：仅人工修剪对硅防御诱导的影响，似乎与包含唾液的自然植食作用存在差异。现有实验室与野外研究均证实，硅基防御的诱导需要达到一定的损伤阈值。在近期针对田鼠-植物互作的研究中，无论是诱导所需的阈值还是防御响应的时序，温室实验与野外实验所观测到的诱导模式均在定量层面上保持一致。 硅基防御对不同类群植食动物的影响存在差异，这或许与不同类群的体型大小、取食行为以及消化生理的差异相关。不过目前仍难以归纳出普适性规律，未来需要开展更多针对野生哺乳类植食动物的研究以阐明此类规律，尤其需要纳入当前尚无相关数据的主要类群，有袋类便是其中一例。 本文指出了若干亟待拓展的新研究方向，以解决硅作为植物防御因子的相关认知盲区——尤其是野外环境下的植物-植食动物互作领域，放牧对防御诱导的影响在此类场景中更难量化。同时本文还讨论了将实验室研究尺度外推至景观尺度研究时所面临的固有障碍：这类景观尺度研究最具生态学相关性，但实施难度也最大，这也是硅生态学领域接下来的核心挑战。