Water Properties Influencing the Abundance and Diversity of Denitrifiers onEichhornia crassipesRoots: A Comparative Study from Different Effluents around Dianchi Lake, China

摘要

To evaluate effects of environmental conditions on the abundance and communities of three denitrifying genes coding for nitrite (nirK, nirS) reductase and nitrous oxide (nosZ) reductase on the roots ofEichhornia crassipesfrom 11 rivers flowing into the northern part of Dianchi Lake. The results showed that the abundance and community composition of denitrifying genes onE. crassipesroot varied with different rivers. ThenirKgene copies abundance was always greater than that ofnirSgene on the roots ofE. crassipes, suggesting that the surface ofE. crassipesroots growth in Dianchi Lake was more suitable for the growth ofnirK-type denitrifying bacteria. The DGGE results showed significant differences in diversity of denitrifying genes on the roots ofE. crassipesamong the 11 rivers. Using redundancy analysis (RDA), the correlations of denitrifying microbial community compositions with environmental factors revealed that water temperature (T), dissolved oxygen (DO), and pH were relatively important environmental factors to modifying the community structure of the denitrifying genes attached to the root ofE. crassipes. The results indicated that the specific environmental conditions related to different source of rivers would have a stronger impact on the development of denitrifier communities onE. crassipesroots.