N2-fixing bacteria are more sensitive to microtopography than nitrogen addition in degraded grassland

Frontiers in Microbiology

Microbiology

Xilai Li¹  Chengyi Li¹  Enrique Valencia²  Guiyao Zhou³  Yan Shi⁴ 

[1] College of Agriculture and Animal Husbandry, Qinghai University, Xining, China;Departamento de Biodiversidad, Ecología y Evolución, Facultad de Ciencias Biológicas, Universidad Complutense de Madrid, Madrid, Spain;German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany;Institute of Biology, Leipzig University, Leipzig, Germany;School of Environment, The University of Auckland, Auckland, New Zealand;

关键词: nitrogen addition;    N-fixing bacteria;    alpine meadow;    slope;    Tibetan Plateau;   

DOI  :  10.3389/fmicb.2023.1240634

 received in 2023-06-15, accepted in 2023-08-25,  发布年份 2023

来源: Frontiers

【 摘 要 】

IntroductionSoil bacteria play a crucial role in the terrestrial nitrogen (N) cycle by fixing atmospheric N2, and this process is influenced by both biotic and abiotic factors. The diversity of N2-fixing bacteria (NFB) directly reflects the efficiency of soil N fixation, and the diversity of NFB in degraded alpine meadow soil may change with different N fertilizing levels and varied slopes. However, how N addition affects the diversity of NFB in degraded alpine meadows, and whether this influence varies with slope, remain poorly understood.MethodsWe conducted an N addition field experiment at three levels (2, 5, and 10 g N·m−2·a−1) to study the effects of N addition on soil NFB diversity on two different slopes in a degraded meadow on the Tibetan Plateau.ResultsThere were significant differences in the dominant bacterial species between the two slopes. The Chao1 index, species richness, and beta diversity of NFB did not differ significantly between slopes, but the Shannon index did. Interestingly, N addition had no effect on the diversity of NFB or the abundance of dominant bacteria. However, we did observe a significant change in some low-abundance NFB. The community composition and diversity of NFB were significantly positively correlated with slope and soil physicochemical properties (e.g., total potassium, pH, and total nitrogen).ConclusionsOur study highlights the variation in NFB communities among different slopes in degraded alpine meadows and their resilience to exogenous N addition. Our results also underscore the importance of considering the effects of micro-topography on soil microbial communities in future studies of alpine ecosystems.

【 授权许可】

Unknown   
Copyright © 2023 Li, Valencia, Shi, Zhou and Li.