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Divergent responses of soil enzyme kinetics to altered precipitation across steppes with varying historical precipitation

文献类型: 外文期刊

作者: Chen, Yaru 1 ; Li, Aogui 1 ; Shi, Ziyue 1 ; Peng, Ziyang 2 ; Wan, Shiqiang 2 ; Liu, Lingli 3 ; Liu, Weixing 1 ;

作者机构: 1.Chinese Acad Agr Sci, Inst Agr Resources & Reg Planning, State Key Lab Efficient Utilizat Arable Land China, Hulunber Grassland Ecosyst Natl Observat & Res Stn, Beijing 100081, Peoples R China

2.Hebei Univ, Inst Life Sci & Green Dev, Coll Life Sci, Baoding 071002, Hebei, Peoples R China

3.Chinese Acad Sci, Inst Bot, State Key Lab Vegetat & Environm Change, Beijing 100093, Peoples R China

4.Univ Chinese Acad Sci, Yuquan Rd, Beijing 100049, Peoples R China

关键词: Drought; Belowground net primary productivity; Microbial biomass; Sensitivity; Rainfall; Soil moisture

期刊名称:APPLIED SOIL ECOLOGY ( 影响因子:5.0; 五年影响因子:5.4 )

ISSN: 0929-1393

年卷期: 2025 年 214 卷

页码:

收录情况: SCI

摘要: Soil extracellular enzymatic catalysis is the rate-limiting step in soil organic matter decomposition, and Vmax and Km are enzyme kinetic parameters reflecting enzyme catalytic capacity. However, it is still far from clear how these enzyme kinetic parameters respond to altered precipitation and subsequently influence soil microbial respiration (Rh). Here, we examined the Vmax and Km of seven soil hydrolytic enzymes and polyphenol oxidase (PPO), Rh, and microbial biomass carbon (MBC) under altered precipitation (- 30%, ambient, and + 30%) across Desert, Typical, and Meadow steppes. The results showed that the Vmax of hydrolytic enzymes and PPO were higher in the meadow than desert and typical steppes. Drought decreased the Vmax of C-, N-, P-degrading enzymes and PPO in the desert and typical steppes, but these changes were not observed in the meadow steppe, indicating the greater sensitivity of Vmax to altered precipitation in drier ecosystems. Similarly, there were the same patterns of Rh and MBC induced by changes in precipitation. However, changes in precipitation differently affected Km depending on enzymes and ecosystem types. Changes in Vmax of enzymes positively correlated with changes in soil moisture and belowground net primary production. Moreover, the Vmax and Km of beta-glucosidase (BG) and the Vmax of leucine aminopeptidase were the best predictors for variability in Rh. Partial least squares path modeling further revealed that Rh response to altered precipitation was directly regulated by kinetic parameters of BG and Vmax of leucine aminopeptidase, rather than by MBC. These findings provide important insights into the linkages between soil hydrolase kinetics and Rh, advancing our understanding of the mechanisms of soil organic matter decomposition under climatic change.

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