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Effects of Land Use Patterns on Diversity and Community Structure of Soil Microbial in Leymus Chinensis Steppe

Author: ZouYuKun
Tutor: ChenXiuRong；YangDianLin
School: Gansu Agricultural University
Course: Grassland biodiversity
Keywords: Leymus chinensis steppe Use patterns Nif gene Ammonia -oxidizing bacteria Diversity Phospholipid fatty acids Deformation gradient gel electrophoresis Phylogenetic analysis
CLC: S812.2
Type: Master's thesis
Year: 2011
Downloads: 73
Quote: 1
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Abstract

Hulunbeir Leymus chinensis steppe object of study, in the lush plant growth season (August 2009), take surface 0-0.2m soil application phospholipid fatty acids (PLFA) analysis different utilization of Leymus chinensis grassland soil ecosystem microbial community structure; using polymerase chain reaction - denaturing gradient gel electrophoresis (PCR-DGGE) and amplification product sequencing methods to study the mowing, grazing and fencing three land use patterns of sheep grass prairie soil nitrogen-fixing microorganisms nifH gene diversity of ammonia-oxidizing bacteria and phylogenetic. The results are as follows: L. chinensis grassland soil microbial community structure change significantly different use patterns. Characterization of soil microbial PLFA total swath cut significantly higher than enclosed and grazing, ENCLOSED PLFA total minimum, correlation analysis showed that the PLFA the total soil microbial biomass carbon (fumigation extraction) highly significant positive correlation. Mowing significantly improve the content of soil bacteria, enclosed actinomycetes were significantly increased in the soil, soil fungi there was no significant change in content in three land use patterns. Mowing plots to characterize bacterial PLFA highest -1 , grazing and fenced plots bacterial content than mow cutting the sample reduced by 27.8% and 49.3%, 29.6 nmol · g ^{. Mowing plots advantages the PLFA type for of a15: 0,15:0,16:0 and 18:0, accounting for 64.6% of the total PLFA the grazing plots advantage PLFA type for i15: 0, i16: 0 and 18 : 1ω9t, accounting for 45.6% of the total PLFA; fenced plots, the dominant the PLFA type for a15: 0,15:0 and i16: 0, accounting for 46.3% of the total PLFA. Most of the nitrogen-fixing microorganisms belonging to the α-proteobacteria the Proteobacteria door in Leymus chinensis grassland soils, respectively, under the red spp, Bradyrhizobium genus, the Mesorhizobium a, red Pseudomonas spp, yellow Xanthomonas genus Azospirillum, the Portuguese sweet and sour genus, methyl Bacillus genus and methyl cyst genus. Symbiotic nitrogen-fixing bacteria mowing plots advantage ecological type, grazing and fenced-like Bacterium Associated with the majority; the nifH gene's diversity to mowing plots highest, while grazing significantly reduced the types of nitrogen-fixing microorganisms Leymus chinensis steppe and the number of reduced nifH gene diversity minimum nifH gene diversity but enclosed plots. The principal component analysis showed that the impact of different land use patterns on nifH gene grazing gt; enclosed gt; mowing. Different use patterns nifH gene and soil physical and chemical factors canonical correspondence analysis showed that the available phosphorus, total phosphorus, nitrate content and pH on microbial community structure of Leymus chinensis grassland soil nitrogen fixation was significantly (P lt; 0.05). Leymus chinensis grassland soil ammonia oxidizing bacteria dominant groups as Asia the nitrification pylori genus Nitrosomonas spp bacteria, accounting for the total number of ammonia oxidizing bacteria by 72.4% and 28.6%, Cluster 4 and Cluster 6 in each plot are the dominant groups, but the proportion of different grazing plots ammonia oxidizing bacteria diversity was highest. Grazing plots the activity of urease and nitrification rates are significantly higher than the other two kinds of use. Different use patterns of soil bacterial communities and soil physical and chemical factors of ammonia oxidation canonical correspondence analysis showed that ammonium nitrogen content of ammonia oxidizing bacteria communities is significant.}

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