The Relationship Between Mycorrhizal Fungi And Soil Microbial Under Tree Species

In this research, BIOLOG method were used to in the field of microbiological ecology to study the microbe communities structure and mucorrhizal fungi under the four tree species in Loess Plateau in Northern Shaanxi Province, and the microbial communities in Pinus tabulaeformis mycorrhizosphere under different ecological conditions. So it is great significance for evaluation mycorrhizal fungi in the role of ecological restoration in regional ecological degradation of soil and vegetation restoration. In this research, we isolated some mycorrhizal-associated fungi from the ectomycorrhizal of Pinus tabulaeformis, and identify these fungi by molecular method as rDNA-ITS, and we study the effects of different substrates on the hydrolyze enzyme of three ectomycorrhizal fungi. The main points of this dissertation are as follows:1. Arbuscular mycorrhizal fungi and the structure of soil microbial communities under four tree species. The results revealed that the rank of the spore density was Hippophae rhamnoides>Sophora viciifolia>Caragana microphylla>Robinia pseudoacacia. The number of bacteria and actinomyces were significantly difference among four treatments, however, there was no significant different in the number of fungi. Principal component analysis showed that different metabolic diversity of forest soil bacteria have significant differences, and Caragana microphylla typical variable value of the soil variability (dispersion) small, Sophora viciifolia and Robinia pseudoacacia were larger variables. The different tree species formed their own unique soil microbial community structure. The density of AMF spore can be used as evaluation of forest soil bacteria metabolism groups and the diversity of biological indicators in the Loess Plateau of northern Shaanxi Province. Soil degradation in the process of vegetation restoration artificially imposed arbuscular mycorrhizal fungus can be improved soil biological traits.2. Microbial communities in Pinus tabulaeformis mycorrhizosphere. The results revealed that the microbes in P. tabulaeformis mycorrhizosphere were more liable to utilize such carbon sources as carbohydrates and amino acids in Ansai and Shangnan, and the number and activity of metabolic carbon sources for the microbes in P. tabulaeformis mycorrhizosphere were higher in Shangnan than in Ansai, and that the average well color development (AWCD) of microbes in the metabolism of same kinds of carbon sources in Shangnan sample was more than two times as much as that in Ansai. The dominant microbe species in P. tabulaeformis mycorrhizosphere in Ansai were the ones that metabolized amino acids. In contrast, the dominant microbe species in Shangnan sample were the ones that metabolized carbohydrates.The microbial community diversity indices and principal component analyses demonstrated that the significant difference between two samples mainly depended on carbohydrate-dominated carbon sources and secondarily on carboxylic acids and amino acids as the last. The activity, community size and diversity of microbes in P. tabulaeformis mycorrhizosphere were higher in warm, humid hilly regions of Shangnan than in Ansai, and the microbial communities in P. tabulaeformis mycorrhizosphere were more stable in dry region of the Loess Plateau in Ansai than in Shangnan.3. Effects of incubation ectomycorrhizal fungi on the soil bacteria functional diversity under Pinus tabulaeformis. Pinus tabulaeformis were inoculated with three kinds of etomycorrhiza fungi inoculum, Suillus bovines, Suillus luteus, and Boletus luridus. The results showed that there had evident simulative effect on improving the soil bacteria community structure. Boletus luridus was the best among the three fungi. The results of Principle Component Analyses revealed that there was great variable among the category of carbon sources which used by soil bacteria community under Pinus tabulaeformis.4. Identify the mycorrhiza-associated fungi of Pinus tabulaeformis by molecular method-rDNA-ITS. The four species mycorrhizal-associated fungi were isolated from the ectomycorrhiza of Pinus tabulaeformis HDTP-1,HDTP-3,HDTP-4 and HDTP-5 were identify by rDNA-ITS. The results shown that HDTP-1 and HDTP-3 were Trichoderma harzianum, While HDTP-4 and HDTP-5 were Mucor hiemalis SA10-6, Mucor hiemalis XSD-98, respectively. Different mycelia of mycorrhizal associated fungi with induced by different capacities to the same ectomycorrhizal fungi; the mycelia of same mycorrhizal associated fungi induced capacity also different with different ectomycorrhizal fungi. Three different ectomycorrhizal fungi had the significant differences in the activity of chitinase,β-1, 3-glucanase and neutral protease. The rank of chitinase activity as follows: Suillus bovines>Boletus luridus > Suillus luteus. The lowestβ-1, 3 glucanase activities was found in Suillus bovines. And the highest neutral protease activity was observed in Boletus luridus.