Plant and Soil Enzyme Activities Regulate CO2 Efflux in Alpine Peatlands After 5 Years of Simulated Extreme Drought

作者：Zhongqing Yan, Enze Kang, Kerou Zhang, Yong Li, Yanbin Hao, Haidong Wu, Meng Li, Xiaodong Zhang, Jinzhi Wang, Liang Yan, Xiaoming Kang · 发表于：Frontiers in Plant Science · 年份：2021 · DOI：10.3389/fpls.2021.756956 · 被引用次数：27 · 研究领域：Peatlands and Wetlands Ecology、Soil Carbon and Nitrogen Dynamics、Coastal wetland ecosystem dynamics

Increasing attention has been given to the impact of extreme drought stress on ecosystem ecological processes. Ecosystem respiration (Re) and soil respiration (Rs) play a significant role in the regulation of the carbon (C) balance because they are two of the largest terrestrial C fluxes in the atmosphere. However, the responses of Re and Rs to extreme drought in alpine regions are still unclear, particularly with respect to the driver mechanism in plant and soil extracellular enzyme activities. In this study, we imposed three periods of extreme drought events based on field experiments on an alpine peatland: (1) early drought, in which the early stage of plant growth occurred from June 18 to July 20; (2) midterm drought, in which the peak growth period occurred from July 20 to August 23; and (3) late drought, in which the wilting period of plants occurred from August 23 to September 25. After 5 years of continuous extreme drought events, Re exhibited a consistent decreasing trend under the three periods of extreme drought, while Rs exhibited a non-significant decreasing trend in the early and midterm drought but increased significantly by 58.48% ( p < 0.05) during the late drought compared with the ambient control. Plant coverage significantly increased by 79.3% ( p < 0.05) in the early drought, and standing biomass significantly decreased by 18.33% ( p < 0.05) in the midterm drought. Alkaline phosphatase, polyphenol oxidase, and peroxidase increased sig...