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

Abstract

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 nitrification-denitrification 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.