The Structure And Ecological Niche Differentiation Of Nitrogen Fixation Microflora In The Rhizosphere Of Ebinur Lake Wetland

The Ebinur Lake wetland has played a prominent role in regulating the climate and maintaining the ecological balance in northern Xinjiang for a long time.It has been called by many scholars as the center of the conjugate evolution of oasis and desertification.The whole wetland is located in the wind tunnel area of the Alashankou,which is also a sensitive area that affects the regional ecological environment.Once the area's ecological environment changes,it will definitely affect the quality of the surrounding environment,and it will have a huge impact on the ecological balance north of the Tianshan Mountains.The wetlands in the Alashankou duct area,mining the fragility of the natural ecosystems and human exploitation of destruction,makes it directly affect the environment of the north and the development of industry and agriculture.In this study,though the time and space of the Wetland Nature Reserve soil nitrogen-fixing bacteria diversity of wetland nature reserve and its correlation with environment,to reveal the wetland ecological distribution characteristics of nitrogen-fixing bacteria and explore the community structure and abundance of nifH in rhizosphere and non-rhizosphere soil of three plants in Ebinur Lake wetland.In order to study the soil quality indicators of the Ebinur Lake wetland in summer,three different plants cover areas?Salicornia Communities,Halocnemum strobilaceum Communities and Reed Communities?were selected in the protected area,and the rhizospheric and non-rhizospheric soil environmental factors for three plants:nitrate nitrogen,water content,total phosphorus,available phosphorus,available potassium,conductivity organic matter,available nitrogen,pH value,total potassium,total nitrogen,and ammonium Nitrogen was measured.The soil physical and chemical properties were analyzed and we found that the pH value of the three plant roots and non-rhizosphere soil was all above 8.0,belonging to alkaline soils.The pH of non-rhizosphere soils is higher than that of rhizosphere soils,and S>H>R,HN>SN>RN,the pH range of 8.12-9.46.The rhizosphere contents of NO₃^--N,NH₄⁺-N,TN,AN and TP in the rhizosphere and non-rhizosphere soil of the three plants were higher than non-rhizosphere soil.Comparing the EC,OM and AK values in the rhizosphere and non-rhizosphere soils of the three species,the other two communities in the rhizosphere were higher than those in the non-rhizosphere soil except for the Reed community.Contrast three kinds of plant rhizosphere and non-rhizosphere soil water content found in addition to the Reed community area for the rhizosphere soil water content significantly greater than the non-rhizosphere,the rest of the two kinds of plant community area are the non-rhizosphere soil water content is greater than the rhizosphere.Comparing the AP,TK,and AK values of the rhizosphere and non-rhizosphere soils of the three plants,in addition to the Salicornia community area soil salt,the rest of the two kinds of plant community area are all the content in the rhizosphere soil is higher than the non-rhizosphere.The nifH gene libraries of rhizosphere and non-rhizosphere soils of three plants were constructed to investigate the diversity and community structure of nifH,a functional gene of nitrogen-fixing microorganisms in rhizosphere and non-rhizosphere soils of different plants.Using real-time quantitative PCR?qPCR?to determine the abundance of nitrogen-fixing in the rhizosphere and non-rhizosphere of different plants.Redundancy analysis?RDA?reveals the relationship between community structure and abundance of nitrogen-fixing bacteria and soil environmental factors in two different habitats:rhizosphere and non-rhizosphere.From the analysis,the richness of the nifH gene library,ACE index,Chao1 index,and Shannon index in non-rhizosphere soils of Salardonia and Halocnemum strobilaceum was higher than that in the rhizosphere soil,but the Reed community had the opposite result.Phylogenetic analysis showed that the dominant species of nif H sequence were Desulfovibrio in the Halocnemum strobilaceum rhizosphere and non-rhizosphere soil,Reed non-rhizosphere soil;the dominant species of nifH sequence were Nodularia in the Reed rhizosphere soil;the dominant species of nif H sequence were Geoalkalibacter and Kosakonia in the Salicornia rhizosphere and non-rhizosphere soil.The abundances of the nifH genes in the rhizosphere soils of the three plants were as follows:Salicornia>Halocnemum strobilaceum>Reed.The abundance of nifH genes in the rhizosphere soils of the three plants was greater than that of the non-rhizosphere soil nifH genes.The abundance of nifH in the Halocnemum strobilaceum sample plots was 9.69 times higher than Reed in rhizosphere soil.In the non-rhizosphere plots,there is a little difference between the three samples.The correlation analysis showed that the abundances of nitrogen-fixing bacteria and nifH genes in the rhizosphere and non-rhizosphere soils of the three plants were related to TN,AN,AP,NH₄⁺-N,NO₃^--N,pH and other factors.These correlation factors can indicate the wetland soil to some extent the interaction between nutrition and the environment factors and potential utilization value.