Drought is the main cause of productivity losses in soybean plants, triggering physiological and biochemical responses, stomatal closure being essential to prevent water losses and thus mitigate the negative effects of drought. Abscisic acid (ABA) is the main molecule involved in stomatal closure under drought conditions along with nitric oxide (• NO). However, the role of • NO in this process is not yet fully understood and contrasting findings about its role have been reported. Most of the assays in the literature have been carried out under in vitro conditions using • NO donors or scavengers, but little is known about the effects of endogenously produced • NO under drought conditions. This study is aimed to determine the pattern of endogenous • NO accumulation from the establishment of water stress and how this relates to stomatal closure and other biochemical and physiological responses. The analysis of soybean plant responses to drought revealed no correlation between whole-leaf • NO accumulation and typical water deficit stress markers. Moreover, • NO accumulation did not explain oxidative damage induced by drought. However, endogenous • NO content correlated with the early stomatal closure. Analysis of stomatal behavior and endogenous • NO content in guard cells through epidermal peel technique showed a stomatal population with high variation in stomatal opening and • NO content under the initial stages of water stress, even when ABA responses are activated. Our data suggest that upon early stress perception soybean plants respond by accumulating • NO in the guard cells to inhibit stomatal closure, potentially through the inhibition of ABA responses. This article is protected by copyright. All rights reserved.

中文翻译：

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• 大豆中的内源性 NO 积累与水分亏缺的初始气孔反应有关


干旱是大豆植物生产力损失的主要原因，会引发生理和生化反应，气孔关闭对于防止水分流失至关重要，从而减轻干旱的负面影响。脱落酸 (ABA) 是干旱条件下与一氧化氮 (• NO) 一起参与气孔关闭的主要分子。然而，NO 在此过程中的作用尚未完全了解，并且已报道了关于其作用的对比研究结果。文献中的大多数测定都是在体外条件下使用NO 供体或清除剂进行的，但对于干旱条件下内源产生的NO 的影响知之甚少。本研究的目的是确定水分胁迫造成的内源性NO 积累的模式，以及这与气孔关闭和其他生化和生理反应的关系。大豆植株对干旱反应的分析表明，全叶NO 积累与典型水分亏缺胁迫标记之间没有相关性。此外，NO 的积累并不能解释干旱引起的氧化损伤。然而，内源性NO 含量与早期气孔关闭相关。通过表皮剥离技术对保卫细胞中的气孔行为和内源性NO 含量进行分析表明，在水分胁迫的初始阶段，即使ABA 反应被激活，气孔群体的气孔开口和NO 含量也存在很大差异。我们的数据表明，在早期感知胁迫时，大豆植物会通过在保卫细胞中积累NO来抑制气孔关闭，可能是通过抑制ABA反应来做出反应。本文受版权保护。版权所有。