Xylem hydraulic failure is a major driver of tree death during drought. However, to better understand mortality risk in trees, especially during hot‐drought events, more information is required on both rates of residual water‐loss from small branches (g _res) after stomatal closure, as well as the phase transition temperature (T _p), beyond which g _res significantly increases. Here, we describe and test a novel low‐cost tool, the DroughtBox, for phenotyping g _res and T _p across species. The system consists of a programmable climatically controlled chamber in which branches dehydrate and changes in the mass recorded. Test measurements show that the DroughtBox maintains stable temperature and relative humidity across a range of set points, a prerequisite for getting accurate g _res and T _p values. Among a study group of four conifer and one angiosperm species, we observed a range of g _res (0.44–1.64 mmol H₂O m⁻² s⁻¹) and T _p (39.4–43.8°C) values. Furthermore, the measured time to hydraulic failure varied between two conifers species and was shortened in both species following a heatwave event. The DroughtBox is a reliable and customizable tool for phenotyping g _res and T _p, as well as for testing models of time to hydraulic failure that will improve our ability to assess climate change impacts on plants.

中文翻译：

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DroughtBox：干旱期间表型残留分支电导及其温度依赖性的新工具。

木质部水力衰竭是干旱期间树木死亡的主要驱动力。然而，为了更好地了解树木的死亡风险，特别是在热干旱事件中，需要更多有关气孔关闭后小树枝残留失水率（g _res）以及相变温度（T _p），超过此值g _res会显着增加。在这里，我们描述并测试了一种新颖的低成本工具DroughtBox，用于对g _res和T _p进行表型分析跨物种。该系统由一个可编程的气候控制室组成，该室中的分支脱水并记录了质量变化。测试测量表明，DroughtBox在一定的设定点范围内保持稳定的温度和相对湿度，这是获得准确的g _res和T _p值的前提。中的研究组四个针叶树和一个被子植物，我们观察到的范围内的克_RES（0.44-1.64毫摩尔ħ ₂ ö米^-2小号^-1）和Ť _p（39.4–43.8°C）值。此外，测得的水力破坏时间在两个针叶树种之间有所不同，并且在热浪事件后两个树种中都缩短了。该DroughtBox是表型分型的可靠和可定制的工具摹_资源和牛逼_p，以及用于测试的时间模型，以液压故障，这将提高我们的评估对植物气候变化影响的能力。