Ghent University, Department of Plant Biotechnology and Bioinformatics, Ghent, Belgium.
VIB Center for Plant Systems Biology, Ghent, Belgium.
J Exp Bot. 2020 Mar 12;71(5):1706-1722. doi: 10.1093/jxb/eraa037.
Drought stress forms a major environmental constraint during the life cycle of plants, often decreasing plant yield and in extreme cases threatening survival. The molecular and physiological responses induced by drought have been the topic of extensive research during the past decades. Because soil-based approaches to studying drought responses are often challenging due to low throughput and insufficient control of the conditions, osmotic stress assays in plates were developed to mimic drought. Addition of compounds such as polyethylene glycol, mannitol, sorbitol, or NaCl to controlled growth media has become increasingly popular since it offers the advantage of accurate control of stress level and onset. These osmotic stress assays enabled the discovery of very early stress responses, occurring within seconds or minutes following osmotic stress exposure. In this review, we construct a detailed timeline of early responses to osmotic stress, with a focus on how they initiate plant growth arrest. We further discuss the specific responses triggered by different types and severities of osmotic stress. Finally, we compare short-term plant responses under osmotic stress versus in-soil drought and discuss the advantages, disadvantages, and future of these plate-based proxies for drought.
干旱胁迫是植物生命周期中的主要环境限制因素，它通常会降低植物的产量，在极端情况下甚至会威胁到植物的生存。在过去几十年中，人们对干旱胁迫诱导的分子和生理响应进行了广泛的研究。由于基于土壤的方法在研究干旱响应方面通常具有挑战性，因为其通量低且条件控制不足，因此开发了平板中的渗透胁迫测定法来模拟干旱。向受控生长培养基中添加聚乙二醇、甘露醇、山梨糖醇或 NaCl 等化合物已变得越来越流行，因为它具有精确控制胁迫水平和起始时间的优势。这些渗透胁迫测定法使人们能够发现非常早期的胁迫响应，即在渗透胁迫暴露后的几秒钟或几分钟内就会发生。在这篇综述中，我们构建了一个详细的渗透胁迫早期响应时间线，重点关注它们如何引发植物生长停滞。我们进一步讨论了不同类型和严重程度的渗透胁迫引发的特定响应。最后，我们比较了在渗透胁迫下和土壤干旱下短期的植物响应，并讨论了这些基于平板的干旱替代物的优缺点和未来发展方向。
