Abscisic acid (ABA) signals regulating stomatal aperture and water loss are usually studied in detached leaves or isolated epidermal peels and at infrequent timepoints. Measuring stomatal ABA responses in attached leaves across a time course enables the study of stomatal behaviour in the physiological context of the plant. Infrared thermal imaging is often used to characterize steady‐state stomatal conductance via comparisons of leaf surface temperature but is rarely used to capture stomatal responses over time or across different leaf surfaces. We used dynamic thermal imaging as a robust, but sensitive, tool to observe stomatal ABA responses in a whole plant context. We detected stomatal responses to low levels of ABA in both monocots and dicots and identified differences between the responses of different leaves. Using whole plant thermal imaging, stomata did not always behave as described previously for detached samples: in Arabidopsis, we found no evidence for fast systemic ABA‐induced stomatal closure, and in barley, we observed no requirement for exogenous nitrate during ABA‐induced stomatal closure. Thus, we recommend dynamic thermal imaging as a useful approach to complement detached sample assays for the study of local and systemic stomatal responses and molecular mechanisms underlying stomatal responses to ABA in the whole plant context.

中文翻译：

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动态热成像确认局部而非快速的全身ABA反应

脱落酸（ABA）信号调节气孔孔径和水分流失通常是在离体的叶子或分离的表皮上以及不经常的时间点进行的。在整个时间过程中测量附着叶片中的气孔ABA响应，可以研究植物生理环境中的气孔行为。红外热成像通常用于通过比较叶片表面温度来表征稳态气孔导度，但很少用于捕获一段时间内或跨不同叶片表面的气孔响应。我们使用动态热成像作为一种健壮但灵敏的工具，可以在整个植物环境中观察气孔ABA的响应。我们在单子叶植物和双子叶植物中检测到对低水平ABA的气孔响应，并确定了不同叶片的响应之间的差异。使用全植物热成像，气孔并不总是像以前对分离样品的描述那样表现：在拟南芥中，我们没有发现快速的系统性ABA诱导的气孔关闭的证据，在大麦中，我们观察到在ABA诱导的气孔期间不需要外源硝酸盐。关闭。因此，我们建议使用动态热成像作为补充独立样品分析的有用方法，以研究整个植物环境中局部和全身性气孔反应以及对ABA气孔反应的潜在分子机制。