Plant hydraulics accentuates the effect of atmospheric moisture stress on transpiration
Plant hydraulics accentuates the effect of atmospheric moisture stress on transpiration
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DOI：
10.1038/s41558-020-0781-5
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发表时间：
2020-06-01
影响因子：
30.7
通讯作者：
Konings, Alexandra G.
中科院分区：
文献类型：
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作者：
Liu, Yanlan;Kumar, Mukesh;Konings, Alexandra G.
蒸散将生产力与陆地和大气之间的水循环联系起来。蒸腾作用是陆地蒸散的主要组成部分，直接联系着水分、能量和碳的循环，并受到土壤和大气的限制（例如，蒸汽压不足（VPD））通过工厂水力过程的水分应力。在气候变化下，这些压力来源可能会有所不同，全球VPD增强，但土壤湿度变化更多变和不确定。在这里，使用模型数据融合的方法，我们表明，在大多数地球系统模型中使用的常见的经验方法来评估ET对土壤水分和VPD的响应，忽略了植物水力学，低估了ET对VPD的敏感性，并通过高估对土壤水分胁迫的敏感性进行补偿。一个水力模型，描述了通过工厂的水运输更好地捕捉ET在高VPD条件下广泛的土壤水分状态。这些研究结果突出了植物水力学在调节大气水分胁迫对升高温度下生物圈-大气相互作用的日益重要性方面的核心作用。
Evapotranspiration links productivity with water cycling between land and atmosphere. A model including plant hydraulics better describes the response of evapotranspiration to stress from vapour pressure deficit and soil moisture under rising temperatures than approaches common in Earth system models.Transpiration, the dominant component of terrestrial evapotranspiration (ET), directly connects the water, energy and carbon cycles and is typically restricted by soil and atmospheric (for example, the vapour pressure deficit (VPD)) moisture stresses through plant hydraulic processes. These sources of stress are likely to diverge under climate change, with a globally enhanced VPD but more variable and uncertain changes in soil moisture. Here, using a model-data fusion approach, we demonstrate that the common empirical approach used in most Earth system models to evaluate the ET response to soil moisture and VPD, which neglects plant hydraulics, underestimates ET sensitivity to VPD and compensates by overestimating the sensitivity to soil moisture stress. A hydraulic model that describes water transport through the plant better captures ET under high VPD conditions for wide-ranging soil moisture states. These findings highlight the central role of plant hydraulics in regulating the increasing importance of atmospheric moisture stress on biosphere-atmosphere interactions under elevated temperatures.