Community Structure Analysis Of Denitrifying Bacteria In Lake And River Wetlands In The Inner Mongolia Plateau Based On T-RFLP Technology

Wetlands are great important environmental resources for human beings, the Inner Mongolia Autonomous Region is rich in wetland resources, and ranks third in China, but it’s wetlands ecosystem is damaged greatly, and appears phenomenon of degradation generally. N2O is one of the most important greeenhouse gases, which could deplete ozone layer most severely. Wetland soils are both sources and sinks of N2O, and contribute greatly to the global warming. Denitrifying bacteria performing demtrification is considered as main process of production of N2O.The method of terminal restriction fragment length polymorphism (T-RFLP) was used to study the community structures and diversities of denitrifying bacteria (?)y key functional genes nosZ in the wetland soils of Hui Teng Xi Le dry-up lake and Xilin river wetland, both in the Inner Mongolia Plateau steppe area. The hierarchical (?)luster analysis and canonical correspondence analysis(CCA) was performed. The reults showed that:At the later dry-up plots in Hui Teng Xi Le dry-up lake site, the diversity indices of denitrifying bacteria were higher, and community structures appeared more complicated. The opposite results were shown at the earlier dry-up plot and the (?)djacent steppe. Their similarity coefficients gradually declined from the middle of he lake to the adjacent steppe, indicating communities is under dynamic succession from wetland to terrestrial environment. Canonical correspondence analysis showed that during drying process, soil moisture and organic matter content Had significant influence on denitrifying bacteria communities. In addition, high pH value(9.69) had inhibitory effect on denitrifying bacteria.In Xilin river, the diversity index of four plots appeared that:DQ>HB>EQ> HX, and evenness index:DQ>HB>HX>EQ. The low similarity index of HX plot compared with XB、DQ、EQ was8.9,4.7, and0.0respectively, river sediments were in specific aquatic environment, where denitrifying bacteria community was unique. A.s Canonical correspondence analysis showed, soil organic matter and total nitrogen content had main effect on denitrifying bacteria. Soil pH value in Xilin river was among8.0-8.7, not inhibiting denitrifying bacteria obviously. Compared with Xilin iver wetland, there was more diversity and more complicated community structure)f denitrifying bacteria in dry-up lake wetland.