Plants affect the spatial distribution of soil microorganisms, but the influence of the local abiotic context is poorly documented. We investigated the effect of a single plant species, the cushion plant Silene acaulis, on habitat conditions, and microbial community. We collected soil from inside (In) and outside (Out) of the cushions on calcareous and siliceous cliffs in the French Alps along an elevation gradient (2,000–3,000 masl). The composition of the microbial communities was assessed by Capillary-Electrophoresis Single Strand Conformation Polymorphism (CE-SSCP). Univariate and multivariate analyses were conducted to characterize the response of the microbial beta-diversity to soil parameters (total C, total N, soil water content, , and pH). Cushions affected the microbial communities, modifying soil properties. The fungal and bacterial communities did not respond to the same abiotic factors. Outside the cushions, the bacterial communities were strongly influenced by bedrock. Inside the cushions, the bacterial communities from both types of bedrock were highly similar, due to the smaller pH differences than in open areas. By contrast, the fungal communities were equally variable inside and outside of the cushions. Outside the cushions, the fungal communities responded weakly to soil pH. Inside the cushions, the fungal communities varied strongly with bedrock and elevation as well as increases in soil nutrients and water content. Furthermore, the dissimilarities in the microbial communities between the In and Out habitats increased with increasing habitat modification and environmental stress. Our results indicate that cushions act as a selective force that counteracts the influence of the bedrock and the resource limitations on the bacterial and fungal communities by buffering soil pH and enhancing soil nutrients. Cushion plants structure microbial communities, and this effect increases in stressful, acidic and nutrient-limited environments.
展开▼
机译：植物会影响土壤微生物的空间分布，但当地非生物环境的影响却鲜有记载。我们调查了一种单一植物物种（气垫植物Silae acaulis）对栖息地条件和微生物群落的影响。我们从法国阿尔卑斯山的钙质和硅质悬崖上的垫子的内侧（内侧）和外侧（外侧）沿海拔梯度（2,000-3,000 masl）收集土壤。通过毛细管电泳单链构象多态性（CE-SSCP）评估了微生物群落的组成。进行了单因素和多因素分析，以表征微生物β多样性对土壤参数（总碳，总氮，土壤含水量， N - NH 4 + ， N - 否 3 - 和pH）。气垫影响了微生物群落，改变了土壤特性。真菌和细菌群落对相同的非生物因素没有反应。在垫子外，细菌群落受到基岩的强烈影响。在垫子内部，由于pH值比开放区域小，两种基岩中的细菌群落高度相似。相比之下，垫子内部和外部的真菌群落同样可变。在垫子外，真菌群落对土壤pH的反应较弱。在垫子内部，真菌群落随基岩和海拔高度以及土壤养分和水分含量的增加而变化很大。此外，随着生境的改变和环境压力的增加，进出生境之间的微生物群落差异也越来越大。我们的研究结果表明，缓冲垫是一种选择性力，可通过缓冲土壤pH值和增强土壤养分来抵消基岩的影响以及细菌和真菌群落的资源限制。垫层植物构成了微生物群落，在压力，酸性和营养有限的环境中，这种作用会增强。
展开▼
