[Responses of Rhizosphere Soil Metabolite and Enzyme Activity Characteristics to Simulated Warming in Alpine Swamp...

By constructing open-top warming chambers in an alpine swamp meadow in a permafrost region of the Qinghai-Xizang Plateau， three experimental groups were established： the control group （CK）， low warming group （T₁： 1.5-2.5℃）， and high warming group （T₂： 3-5℃）， to evaluate the effects of warming on rhizosphere soil enzyme activities and metabolites. The results indicated that rising temperatures significantly affected soil enzyme activities. Compared to that in CK， β-glucosidase activity was markedly increased in the T₁ group and further enhanced in the T₂ group； sucrase activity was significantly decreased in the T₁ group， whereas it exhibited a significant increase in the T₂ group； cellulase and polyphenol oxidase activities were notably decreased in the T₁ group； and ascorbate peroxidase activity was significantly reduced in the T₂ group. Metabolomics analysis revealed that amino acid metabolism and secondary metabolite accumulation were significantly promoted in the T₁ group. In contrast， the T₂ group showed a marked increase in lipid metabolism， with lipid metabolite abundance significantly higher than that in CK. Volcano plot and principal component analysis （PCA） results demonstrated that warming significantly altered soil metabolite composition and metabolic network structure. Pearson correlation analysis identified significant associations between metabolites and enzyme activities in the rhizosphere soil， such as a strong positive correlation between PA （16∶0/16∶0） and the activities of sucrase and β-glucosidase.