The ecosystem wilting point defines drought response and recovery of a Quercus‐Carya forest
The ecosystem wilting point defines drought response and recovery of a Quercus‐Carya forest
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生态系统枯萎点定义了栎树和山核桃林的干旱响应和恢复
DOI：
10.1111/gcb.16582
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发表时间：
2023
影响因子：
11.6
通讯作者：
Sack, Lawren
中科院分区：
文献类型：
--
作者：
Wood, Jeffrey D.;Gu, Lianhong;Hanson, Paul J.;Frankenberg, Christian;Sack, Lawren
土壤和大气干旱日益威胁着世界各地的植物生存和生产力。然而，概念上的差距限制了我们预测气候变化下生态系统尺度干旱影响的能力。在这里，我们介绍了生态系统萎蔫点（EWP），一个属性，集成了干旱响应的生态系统的植物群落在土壤-植物-大气连续体。具体地说，EPWP定义了一个阈值，低于该阈值，根系吸收土壤水分的能力和叶片维持气孔功能的能力就会大大减弱。我们结合生态系统通量和叶水势测量，从“生态系统压力-体积（PV）曲线”中推导出aQuercus-Caryaforest的EWP，这类似于组织水平的技术。当群落黎明前叶水势（Ewp）高于Ewp（=-2.0 MPa）时，森林对环境动态的响应很强。当CO2排放量低于CO2排放量时，森林对环境变化变得不敏感，并在近2个月内成为二氧化碳的净来源。因此，CODEWP是界定生态系统功能状态显著变化的一个阈值。虽然有降雨诱导的生态系统气体交换的恢复浸泡雨，结构和生理损伤的遗产抑制冠层光合能力。虽然在16个生长季节中，只有10%的土壤水分观测值低于100 EWP，但森林通常只有2-4周的强烈干旱才能达到100 EWP，因此高度依赖频繁的降雨来补充土壤水分供应。基于对根密度分布和土壤水分特征曲线的自下而上的分析，我们提出，土壤水分获取能力是ΨEWP的主要决定因素，生态系统中的物种需要兼容的叶水平特征，例如膨压丧失点，以便叶片萎蔫与无法从土壤中提取更多水分相协调。
Soil and atmospheric droughts increasingly threaten plant survival and productivity around the world. Yet, conceptual gaps constrain our ability to predict ecosystem‐scale drought impacts under climate change. Here, we introduce the ecosystem wilting point (ΨEWP), a property that integrates the drought response of an ecosystem's plant community across the soil–plant–atmosphere continuum. Specifically, ΨEWPdefines a threshold below which the capacity of the root system to extract soil water and the ability of the leaves to maintain stomatal function are strongly diminished. We combined ecosystem flux and leaf water potential measurements to derive the ΨEWPof aQuercus‐Caryaforest from an “ecosystem pressure–volume (PV) curve,” which is analogous to the tissue‐level technique. When community predawn leaf water potential (Ψpd) was above ΨEWP(=−2.0 MPa), the forest was highly responsive to environmental dynamics. When Ψpdfell below ΨEWP, the forest became insensitive to environmental variation and was a net source of carbon dioxide for nearly 2 months. Thus, ΨEWPis a threshold defining marked shifts in ecosystem functional state. Though there was rainfall‐induced recovery of ecosystem gas exchange following soaking rains, a legacy of structural and physiological damage inhibited canopy photosynthetic capacity. Although over 16 growing seasons, only 10% of Ψpdobservations fell below ΨEWP, the forest is commonly only 2–4 weeks of intense drought away from reaching ΨEWP, and thus highly reliant on frequent rainfall to replenish the soil water supply. We propose, based on a bottom‐up analysis of root density profiles and soil moisture characteristic curves, that soil water acquisition capacity is the major determinant of ΨEWP, and species in an ecosystem require compatible leaf‐level traits such as turgor loss point so that leaf wilting is coordinated with the inability to extract further water from the soil.
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影响因子：
6.9
作者：
Boyer JS
通讯作者：
Boyer JS
将经典的土壤永久萎蔫点概念（−15,000hPa）与对比土壤质地下小麦和大麦植物的生物枯萎进行比较
影响因子：
6.7
作者：
L. H. Wiecheteck;N. F. Giarola;Renato P. de Lima;C. A. Tormena;L. C. Torres;A. L. D. Paula
通讯作者：
A. L. D. Paula
影响因子：
--
作者：
B. Myers
通讯作者：
B. Myers
影响因子：
6.9
作者：
H. Richter
通讯作者：
H. Richter
影响因子：
2.6
作者：
D. Ciruzzi;S. Loheide
通讯作者：
D. Ciruzzi;S. Loheide