接种菌根真菌对湿生植物根际土壤硝化反硝化活性的影响及其微生物机制

Effects of Mycorrhizal Fungi on Nitrification and Denitrification in the Rhizospheric Soil of Aquatic Plants and Its Microbial Mechanism

为探究接种菌根真菌对湿生植物根际土壤硝化-反硝化作用的影响,以湿生植物旱伞草和石菖蒲为材料,接种筛选自本地植物根系及根际土壤的菌根真菌混合菌种MF-MD为试验组,并设置未接种植物作为对照组.在水体氮素富营养化条件下种植3个月,然后测定植物根际土壤硝化反硝化活性.结果表明,接种MF-MD能促进两种植物根际土壤硝化反应,同时接种MF-MD促进了旱伞草根际土壤反硝化作用但是抑制了石菖蒲根际土壤反硝化作用.从接种后植物根际土壤微生物量,硝化细菌与反硝化细菌群落结构变化等角度分析了引起土壤硝化-反硝化反应发生变化的原因.发现接种处理的试验组湿生植物根际土壤微生物量(soil microbial biomass,SMB)高于对照组但差异不显著,且与对照组相比,试验组与土壤硝化反硝化作用相关的微生物群落结构发生变化.此试验对于研究菌根真菌结合湿生植物去除富营养化水体中的N元素具有积极意义.

To investigate the effect of mycorrhizal fungi inoculation on nitrification-denitrification in the rhizospheric soil of aquatic plants,Cyperus alternifolius and Acorus tatarinowii were inoculated with the strain MF-MD obtained from local soil.Uninoculated plants served as the control group.The plants were cultivated for 3 months under nitrogen eutrophication in water,and then the nitrification and denitrification activities in the rhizospheric soil were determined.The results showed that inoculation with MF-MD promoted nitrification in the rhizospheric soil of both plants.However,MF-MD inoculation promoted denitrification in the rhizospheric soil of Cyperus alternifolius but inhibited denitrification in the rhizospheric soil of Acorus tatarinowii.The mechanism of soil nitrificationdenitrification activity was analyzed by measuring the changes in the community structure of nitrifying bacteria and denitrifying bacteria in the microbial biomass of the rhizospheric soil.It was found that the rhizospheric soil microbial biomass(SMB)of the experimental group was higher than that of the control group and that the changes in the microbial community structure related to soil nitrification and denitrification differed between groups.This study contributes to an understanding of how mycorrhizal fungi combined with aquatic plants can remove N content in eutrophic water.