Response Of Soil Microbial Community Structure To Halophytic Vegetation Succession

The Yellow River delta wetland ecosystem is fragile in ecological environent,which hasmany researchers,attention in recent years. Soil microorganism can improve the ecosystemenvironment, so the regional distribution regularity and the response rules to halophyticvegetation succession is a research hotspot in recent years. Yellow River Delta is a natural andrare experimental site with vegetation succession has provided the possibility for the researchon dynamic evolution of soil microbial community.Using the method of drying moisture under different vegetation communities, the soilwater content is Imperata>Bare land> Suaeda Heteroptera> Aeluropus littoralis> Apocynumvenetum. Using soil electrical conductivity (EC) represent the change of salt content, theresults as follows: Bare land> Aeluropus littoralis and Suaeda salsa> Imperata cylindrica andApocynum venetum. Using direct culture microbial method show that with the succession ofsaline vegetation quantity, the number of soil bacteria and actinomycetes are increasing.Bymolecular biology techniques using16SrDNA gene universal primer to amplified16SrDNAgene of bacteria from above vegetation soil, construct a16SrDNA clone library. By sequencingand phylogenetic analysis, different salt vegetation on the soil bacterial diversity were studied.The evenness and richness of several soil microorganisms are tended to be the same. Thediversity of bacterial in Bare land soil is in the least, bacterial diversity increase with vegetationcoverage.Analysis of inspection and removal of chimeric weird sequences usingCHECK-CHIMERA software. Using the ClustalW2multiple comparison analysis to find OUT,using Mega5.0software (Neighbor-Joining) to constructe phylogenetic tree system.The resultsshow that soil bacteria from different saline vegetation,include Proteobacteria、Chloroflexi、Acidobacteria、Bacteroidetes、planctomycetales、Actinobaeteria、Firmicutes、Verrucomicrobia、Cyanobacteria、Deinococcus-Thermus. Proteobacteria is the dominant deformation bacteria.Bacteroidetes is the dominant groups in light Salt soil, Deinococcus-Thermus were thedominant groups in the bare land, so Deinococcus-Thermus demonstrate the soil environmental has been deterioratede, Acidobacteria is in a large proportion in Imperata cylindrica (lightsalt) and in bluish dogbane (light salt). Firmicutes in saline soil with larger proportion canwithstand extreme environments. Most soil microorganisms showed geographical distributionof certain. Chloroflexi bacteria in imperata cylindrica vegetation occupies a large proportion,occupies lessly in the other vegetation soil. Chloroflexi did not show the response of vegetationsuccession with soil salinity. Distribution of microorganism is not only affected by the mainfactors of salt also affected by the rhizosphere soil vegetation. Application of Sorensensimilarity index, we investigated the bacterial community structure when succession stages is inthe same time. When the vegetation succession is in the same time, the microbial communitystructure has greater similarity.