Chin J Plant Ecol ›› 2021, Vol. 45 ›› Issue (青藏高原高寒草地:格局与过程): 0-0.DOI: 10.17521/cjpe.2020.0139

   

Soil enzyme activities and their influencing factors among different alpine grasslands in the Qinghai-Xizang Plateau

Ziwei Wang1,Songze Wan2,Hongmao Jiang1,Yang Hu1,Shuqin Ma3,Youchao Chen4,Xuyang Lu1   

  1. 1. Institute of Mountain Hazards and Environment (IMHE), Chinese Academy of Sciences
    2. School of Forestry,Jiangxi Agricultural University
    3. College of Tourism, Henan Normal University
    4. Wuhan Botanical Garden, Chinese Academy of Sciences
  • Received:2020-05-11 Revised:2020-08-04 Online:2021-04-20 Published:2020-08-10
  • Contact: Xuyang Lu
  • Supported by:
    Nation Natural Science Foundation of China;Nation Natural Science Foundation of China

Abstract: Aims As a key factor of nutrient cycling in ecosystem, soil enzyme activity is an important indicator of soil quality and ecosystem function. However, there were few studies on the differences of soil enzyme activities among different alpine grassland ecosystem types. Thus, the aims of this study were to compare the differences of soil enzyme activities among five different alpine grassland types and to reveal their influencing environmental factors in the Qinghai-Xizang Plateau. Methods 21 samples of five alpine grassland types, including alpine meadow (AM), alpine steppe (AS), alpine meadow steppe (AMS), alpine desert steppe (ADS) and alpine desert (AD) in northern Qinghai-Xizang Plateau, were selected for field in-situ investigation and sampling. The activities of 14 enzymes involved in the cycling of carbon (C), nitrogen (N) and phosphorus (P) were determined, and the relationships between enzymatic activities and environmental factors in alpine grassland were established. Important findings The activities of C-acquisition (invertase, cellulase, β-1,4-glucosidse, polyphenol oxidase and peroxidase), P-acquisition (alkaline phosphatase) enzymes and two N-acquisition (arylamidase and nitrite reductase) were significantly different among different alpine grassland types. And the correlations were found among C-acquisition, N-acquisition and P-acquisition enzymes. A significant positive correlation was found between invertase and alkaline phosphatase, between cellulase and N-acetyl-α-D-glucosaminidase. A significant negative correlation was found between polyphenol oxidase and nitrite reductase, N-acetyl-β-D-glucosaminidase. Soil organic matter (SOM) content, gram negative bacteria (G-) content, ratio of nitrogen to phosphorus (N:P), gram positive bacteria (G+) content, bacteria content, actinomycetes content, total nitrogen (TN) content and fungi content were the key factors which influencing soil enzyme activity among the 19 environmental indicators, and SOM content had the greatest impact (explains 11.9%). The results demonstrated that the activities of C-acquisition, P-acquisition and two N-acquisition (arylamidase and nitrite reductase) enzymes were significantly different among different types of alpine grassland. And soil enzyme activities were mainly controlled by SOM content, microbes and N elements in alpine grassland ecosystems. The results of this study will provide a scientific reference for predicting soil enzyme activity in the alpine grassland ecosystem of the Qinghai-Xizang Plateau and its response to global changes, and provide a theoretical basis for maintaining the primary productivity of alpine grassland ecosystem.

Key words: alpine meadow, alpine steppe, soil enzyme activity, soil microbe, environmental factors