青海三江源高寒草甸土壤微生物功能多样性的海拔分布

本研究以空间替代时间的方法,在青海三江源国家级自然保护区,以每隔200 m-300 m的海拔差异,从海拔3220 m(S1)到4790 m(S6)共设立6个海拔梯度的高寒草甸土壤样地为研究对象,利用Biolog生态板法研究了不同海拔土壤微生物碳源利用功能多样性分布特征,试图分析海拔变化对多样性分布特征的影响及其响应。结果表明,随着海拔的升高,微生物群落碳源利用功能多样性指数整体呈现先下降后上升的趋势,与AWCD变化趋势一致;DCA分析显示不同海拔土壤微生物对碳源代谢结构有一定的空间差异;不同海拔梯度的土壤微生物对6类碳源的利用程度存在差异,其中多聚化合物为优势碳源;从CCA和Partial mantel分析得知,土壤微生物群落的碳源利用功能多样性的海拔分布格局与海拔高度、全磷含量、有效磷含量呈显著相关关系,而与植物多样性没有相关性。了解不同海拔下土壤微生物对碳源利用强度,可为揭示三江源的微生物过程提供基础数据。

Altitude Distribution of Soil Microbial Function Diversity in Alpine Meadow in Sanjiangyuan Region, Qinghai Province

ABSTRACT: Method of spatial variation instead of temporal variation was used in the study, six sites, which from 3220 m (S1) to 4790 m (S6), were established along every 200-300 m altitude in the alpine meadow in Qinghai Sanjingyuan National Reserve. Biolog Eco-Plates method was used to explore the distribution patterns of functional diversity of carbon source utilization along an elevational gradient, trying to analyze the effect of altitude changes on the patterns and its response. The results showed that, with the increase of alti- tude, microbial functional diversity indexes were in a trend of decreasing first and then rising, which was similar to the variation of AWCD. Microbial metabolic structure at different altitudes presented certain degree differences detected by Detrended correspondence analysis.The utilization degree of six carbon sources were different, and the polymers was the dominant carbon source. Canonical corre- spondence analysis and partial Mantel test indicated that altitude, phosphorus and available phosphorus content, but not plant diversity, significantly correlated with function diversity distribution pattern in Qinghai Sanjingyuan National Reserve. Understanding carbon uti- lization degree at different altitude can provide fundamental data to reveal microbial life process in Sanjingyuan.