Silicon (Si), the second most abundant element in Earth’s crust, exerts beneficial effects on the growth and productivity of a variety of plant species under various environmental conditions. However, the benefits of Si and its importance to plants are controversial due to differences among the species, genotypes, and the environmental conditions. Although Si has been widely reported to alleviate plant drought stress in both the Si-accumulating and nonaccumulating plants, the underlying mechanisms through which Si improves plant water status and maintains water balance remain unclear. The aim of this review is to summarize the morphoanatomical, physiological, biochemical, and molecular processes that are involved in plant water status that are regulated by Si in response to drought stress, especially the integrated modulation of Si-triggered drought stress responses in Si accumulators and intermediate- and excluder-type plants. The key mechanisms influencing the ability of Si to mitigate the effects of drought stress include enhancing water uptake and transport, regulating stomatal behavior and transpirational water loss, accumulating solutes and osmoregulatory substances, and inducing plant defense- associated with signaling events, consequently maintaining whole-plant water balance. This study evaluates the ability of Si to maintain water balance under drought stress conditions and suggests future research that is needed to implement the use of Si in agriculture. Considering the complex relationships between Si and different plant species, genotypes, and the environment, detailed studies are needed to understand the interactions between Si and plant responses under stress conditions.

中文翻译：

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硅在植物干旱胁迫反应中的作用

硅（Si）是地壳中第二丰富的元素，在各种环境条件下对多种植物物种的生长和生产力产生有益的影响。然而，由于物种、基因型和环境条件的差异，硅的益处及其对植物的重要性存在争议。尽管硅已被广泛报道可以缓解积硅植物和非积硅植物的干旱胁迫，但硅改善植物水分状况和维持水平衡的潜在机制仍不清楚。本综述的目的是总结硅响应干旱胁迫而调节植物水分状态的形态解剖学、生理学、生化和分子过程，特别是硅蓄积器中硅引发的干旱胁迫反应的综合调节以及中间型和排除型植物。影响硅减轻干旱胁迫影响的能力的关键机制包括增强水的吸收和运输、调节气孔行为和蒸腾失水、积累溶质和渗透调节物质，以及诱导与信号事件相关的植物防御，从而维持整体生长。植物水分平衡。本研究评估了硅在干旱胁迫条件下维持水平衡的能力，并提出了未来在农业中应用硅所需的研究建议。考虑到硅与不同植物物种、基因型和环境之间的复杂关系，需要进行详细研究以了解胁迫条件下硅与植物反应之间的相互作用。