不同湿地植物脱氮效果与根际土壤微生物群落功能多样性特征分析

Nitrogen Removal Efficiencies and Rhizosphere Soil Microbial Community Functional Diversities of Different Plants in Constructed Wetlands

为研究水平潜流型人工湿地中不同植物脱氮效果及对土壤微生物的影响,采集水样测定脱氮效率,采集芦苇根际土壤、香蒲根际土壤和对照土壤(不种植物),利用Biolog技术研究不同处理土壤微生物群落代谢功能多样性特征.结果表明:①与对照相比,种植芦苇和香蒲可提高水平潜流型人工湿地7%~33%的NH 3-N去除率.②芦苇和香蒲根际土壤的碳源利用率增加,并显著高于对照土壤;香蒲根际土壤的碳源利用率高于芦苇根际土壤.芦苇和香蒲根际土壤微生物均对碳水化合物的相对利用率较高(>48.0%),对照土壤微生物对碳水化合物和聚合物的相对利用率均较高,分别为34.4%和32.7%.③芦苇和香蒲根际土壤微生物的丰富度指数、Shannon-Wiener多样性指数和Shannon-Wiener均匀度指数均显著高于对照土壤.④主成分分析(principal component analysis,PCA)结果表明,芦苇和香蒲根际土壤微生物与对照土壤微生物对碳源的利用特征均存在显著差异,而不同植物对土壤微生物碳源利用多样性的影响较小.研究显示,种植植物可改善水平潜流型人工湿地的脱氮效率,增加根际土壤微生物群落功能多样性,而不同植物(芦苇和香蒲)对脱氮效率和根际土壤微生物群落组成的影响无显著差异,因此在种植植物时可根据当地条件进行选择.

In order to reveal the effects of different plants on nitrogen removal efficiency and soil microorganisms in subsurface flow constructed wetlands,water and soil samples were collected to determine nitrogen removal efficiencies and soil microbial community.The functional diversities of microbial community in the control soil(without plant),the rhizosphere soil of reed(Phragmites communis)and cattail(Typhae latifolia)were determined using Biolog method.The results were as follows:(1)The NH 3-N removal rate could be increased by 7%-33%in the wetland with reed and cattail than control.(2)The increasing rates of carbon utilization were higher in the rhizosphere soil of reed and cattail than in the control.The relative utilization rates of carbohydrate were higher in the rhizosphere soil of reed and cattail than that of the control soil.The relative utilization rates of carbohydrate in rhizosphere soil were higher and they were more than 48.0%.The soil microorganism had higher relative utilization rate of carbohydrate and polymer in the control and the values researched 34.4%and 32.7%,respectively.(3)The richness index,Shannon-Wiener diversity index,and Shannon-Wiener evenness index of soil microorganism were significantly higher in rhizosphere soil of reed and cattail than the control soil.(4)The principle component analysis(PCA)showed that the carbon utilization of soil microbial communities was significantly different between rhizosphere soil and control.However,the difference in the nitrogen removal efficiency and microbial community between rhizosphere soils of reed and cattail was small.In conclusion,plant cultivation could improve the nitrogen removal rate of the subsurface constructed wetlands and increase microbial community functional diversity of the rhizosphere soil,and the indexes were not significantly different between rhizosphere soils of reed and cattail.Thus,plant species could be selected according to the local conditions.