Coordination of physiological traits involved in drought-induced mortality of woody plants.
Coordination of physiological traits involved in drought-induced mortality of woody plants.
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DOI：
10.1111/nph.13461
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发表时间：
2015-10
期刊：
影响因子：
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通讯作者：
Maurizio Mencuccini;F. Minunno;Yann Salmon;J. Martínez‐Vilalta;T. Hölttä
中科院分区：
文献类型：
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作者：
Maurizio Mencuccini;F. Minunno;Yann Salmon;J. Martínez‐Vilalta;T. Hölttä
对干旱引起的死亡率进行准确建模具有挑战性。提出了一个稳态模型，将干旱发展期间的木质部和韧皮部运输、叶级气体交换和植物碳水化合物消耗结合起来。基于专家知识和文献综述对参数不确定性进行了贝叶斯分析。该模型通过结合涵盖 170 个物种的 6 个数据汇编进行测试，使用木质部电导率、气孔导度和叶片饱满度对水势的敏感性信息。确定了稳态下植物失效的可能模式（即碳（C）饥饿、水力失效和韧皮部运输失效）。碳饥饿主要发生在等水气孔控制的参数空间中，而水力衰竭则普遍发生在木质部对栓塞敏感的空间中。相对于碳饥饿，韧皮部运输失败发生在光合作用低敏感性和生长对植物水分状况高敏感性的条件下。这三种失效模式可能是沿着生理脆弱性的两个轴的极端情况，一个以水供需平衡为特征，另一个以碳水化合物源和汇之间的平衡为特征。由于生理脆弱性的表达是协调的，我们认为不同的失效模式应该以大致相同的可能性发生，这与使用最优理论的预测一致。
Accurate modelling of drought-induced mortality is challenging. A steady-state model is presented integrating xylem and phloem transport, leaf-level gas exchange and plant carbohydrate consumption during drought development. A Bayesian analysis of parameter uncertainty based on expert knowledge and a literature review is carried out. The model is tested by combining six data compilations covering 170 species using information on sensitivities of xylem conductivity, stomatal conductance and leaf turgor to water potential. The possible modes of plant failure at steady state are identified (i.e. carbon (C) starvation, hydraulic failure and phloem transport failure). Carbon starvation occurs primarily in the parameter space of isohydric stomatal control, whereas hydraulic failure is prevalent in the space of xylem susceptibility to embolism. Relative to C starvation, phloem transport failure occurs under conditions of low sensitivity of photosynthesis and high sensitivity of growth to plant water status. These three failure modes are possible extremes along two axes of physiological vulnerabilities, one characterized by the balance of water supply and demand and the other by the balance between carbohydrate sources and sinks. Because the expression of physiological vulnerabilities is coordinated, we argue that different failure modes should occur with roughly equal likelihood, consistent with predictions using optimality theory.