Plant hydraulics, stomatal control and the response of a tropical forest to water stress over multiple temporal scales

编号 040034705

推送时间 20220613

研究领域 森林培育 

年份 2022 

类型 期刊 

语种 英语

标题 Plant hydraulics, stomatal control and the response of a tropical forest to water stress over multiple temporal scales

来源期刊 Global Change Biology

期 第347期

发表时间 20220404

关键词 carbon cycles;  El Ni?o;  evapotranspiration;  gross primary productivity;  plant hydraulics; 
stomata control;  tropical forest;  water stress; 

摘要 Many tropical regions are experiencing an intensification of drought, with increasing severity and frequency. The ecosystem response to these changes is still highly uncertain. On short time scales (from diurnal to seasonal), tropical forests respond to water stress by physiological controls, such as stomatal regulation and phenological adjustment, to cope with increasing atmospheric water demand and reduced water supply. However, the interactions among biological processes and co-varying environmental factors that determine the ecosystem-level fluxes are still unclear. Furthermore, climate variability at longer time scales, such as that generated by ENSO, produces less predictable effects because it depends on a highly stochastic combination of factors that might vary among forests and even between events in the same forest. This study will present some emerging patterns of response to water stress from five years of water, carbon, and energy fluxes observed on a seasonal tropical forest in central Panama, including an increase in productivity during the 2015 El Ni?o. These responses depend on the combination of environmental factors experienced by the forest throughout the seasonal cycle, in particular, increase in solar radiation, stimulating productivity, and increasing vapor pressure deficit and decreasing soil moisture, limiting stomata opening. These results suggest a critical role of plant hydraulics in mediating the response to water stress over a broad range of temporal scales (diurnal, intraseasonal, seasonal and interannual), by acclimating canopy conductance to light and vapor pressure deficit during different soil moisture regimes. A multilayer photosynthesis model coupled with a plant hydraulics scheme can reproduce these complex responses. However, results depend critically on parameters regulating water transport efficiency and the cost of water stress. As these costs have not been properly identified and quantified yet, more empirical research is needed to elucidate physiological mechanisms of hydraulic failure and recover, for example embolism repair and xylem regrowth.

服务人员 孙小满

服务院士 尹伟伦

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