Combining hydraulic

and carbon-related measurements can help elucidate drought-induced plant mortality. To study drought mortality mechanisms, seedlings of two woody species, including the anisohydric Robinia pseudoacacia and isohydric Quercus acutissima, were cultivated in a greenhouse and subjected to intense drought by withholding water and mild drought by adding half of the amount of daily water lost. Patterns of leaf and root gas exchange, leaf surface areas, growth, leaf and stem hydraulics, and carbohydrate dynamics were determined in drought-stressed and control seedlings. We detected a complete loss of hydraulic conductivity and partial depletion of total nonstructural carbohydrates contents (TNC) in the dead seedlings. We also found that intense drought triggered a more rapid decrease in plant water potential and a faster drop in net photosynthesis below zero, and a greater TNC loss in dead seedlings than mild drought. Additionally, anisohydric R. pseudoacacia suffered a rapider death than the isohydric Q. acutissima. Based on these findings, we propose that hydraulic conductivity loss and carbon limitation jointly contributed to drought-induced death, while the relative contributions could be altered by drought intensity. We thus believe that it is important to illustrate the mechanistic relationships between stress intensity and carbon-hydraulics coupling in the context of isohydric vs. anisohydric hydraulic strategies.

中文翻译：

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水分利用策略和干旱强度定义了幼苗死亡期间水力衰竭和碳水化合物消耗的相对贡献。

结合液压

与碳有关的测量值可以帮助阐明干旱引起的植物死亡率。为了研究干旱的死亡机理，研究了两种木本植物的幼苗，包括异水刺槐和等水栎木种植在温室中，通过保留水分使其遭受强烈干旱，通过增加每日损失的一半水分而遭受轻度干旱。确定了干旱胁迫和对照幼苗的叶片和根系气体交换模式，叶片表面积，生长，叶片和茎的水力学以及碳水化合物动态。我们检测到死苗中水力传导率完全丧失，总非结构性碳水化合物含量（TNC）的部分消耗。我们还发现，与轻度干旱相比，强烈干旱引发植物水势下降更快，净光合作用下降更快，低于零，死苗中TNC损失更大。此外，比等渗Q. acutissima的等渗R. pseudoacacia死亡更快。。基于这些发现，我们认为水力传导率的损失和碳的限制共同导致干旱引起的死亡，而相对的贡献可以被干旱强度改变。因此，我们认为，重要的是要说明在等水压与等水压水力策略的背景下，应力强度与碳液压耦合之间的机械关系。