Intra‐Specific Variability in Plant Hydraulic Parameters Inferred From Model Inversion of Sap Flux Data
Intra‐Specific Variability in Plant Hydraulic Parameters Inferred From Model Inversion of Sap Flux Data
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DOI：
10.1029/2021jg006777
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发表时间：
2022-05
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影响因子：
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通讯作者：
Yaojie Lu;Brandon P. Sloan;S. Thompson;A. Konings;G. Bohrer;A. Matheny;Xue Feng
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文献类型：
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作者：
Yaojie Lu;Brandon P. Sloan;S. Thompson;A. Konings;G. Bohrer;A. Matheny;Xue Feng
了解植物的水力调节对于预测植物和生态系统对预计的干旱胁迫增加的反应至关重要。植物水力调节是由可观察的、多样化的植物水力特性控制的，这些特性可以在同一物种的不同个体之间变化，也可以在不同物种之间变化。与其他更容易测量的特性(例如，比叶面积)相比，直接测量一系列生态系统中的植物水力特性仍然有限。此外，通常在树叶或树枝水平上进行的植物水力特性测量，很难按比例调整到通常用于预测植物和生态系统通量的整株数值。在这项研究中，通过对植物水分利用(即树干流量)、土壤性质和气象数据的观测，推断出多种全植物水力参数。我们使用马尔可夫链蒙特卡罗模型反演方法获得了植物水力参数的最佳估计和不确定性，这些参数反映了植物的有效栓塞力和气孔对植物水势下降的敏感性。然后，我们使用模型中的推断值来估计整棵树的用水量和等含水率。这种方法可靠地推断出具有足够特异性的全株参数值，以解决种间和种内差异，从而补充了对性状的耗时和劳动密集型的直接测量。
Understanding plant hydraulic regulation is critical for predicting plant and ecosystem responses to projected increases in drought stress. Plant hydraulic regulation is controlled by observable, diverse plant hydraulic traits that can vary as much across individuals of the same species as they do across different species. Direct measurements of plant hydraulic traits from a range of ecosystems remain limited in comparison to other, more readily measured traits (e.g., specific leaf area). Furthermore, plant hydraulic trait measurements, often made at leaf or branch levels, are not easily scaled to whole‐plant values that are typically used to predict plant and ecosystem fluxes. In this study, multiple whole‐plant hydraulic parameters are inferred from observations of plant water use (i.e., sap flow), soil properties, and meteorological data. We use a Markov Chain Monte Carlo model inversion approach to obtain the best estimates and uncertainty of plant hydraulic parameters that capture whole‐plant effective embolism resistance and stomatal sensitivity to decreasing plant water potential. We then use the inferred values in the model to estimate whole‐tree water use and isohydricity. This approach reliably infers whole‐plant parameter values with enough specificity to resolve inter‐ and intra‐specific differences, and thus supplements time‐ and labor‐intensive direct measurements of traits.