Studies On The Diversity Of Soil Fungi In The Alpine Grassland Of Eastern Qilian Mountains

As a main part of the agricultural ecosystem of grassland, soil microorganisms play vital roles in many processes, such as energy flowing and subtance conversion & cycling as well as soil developing and maturation. It is a sensitive index of any variation in environmental conditions as well. Constitutions and quantities of population are two key parameters for evaluating the soil quality. Therefore, it is very significative to study quantity of soil microbial population, diversity of population, ecological distribution characteristics and physiological fuction groups enhancing productivity of grassland ecosystem for sustainable development. The fungi are a kind of extensive eukaryotes microorganism, The fungi form the most microorganism amount of soil, resolve the organic matter, offer nutrient for plant and are healthy instruction thing for ecosystem. Fungal diversity has played important function in maintain the biosphere ecological balance and offer the undeveloped living resources to mankind in a large amounting, therefore, the study on soil fungal species, quantitative composition, ecological distribution et al, in order to reveal the fungal community, species diversity and to provide evidence for effective protection and comprehensive development of alpine grassland in Eastern Qilian mountains.In this study, seven different representative vegetation types of alpine grassland in Eastern Qilian Mountains, which were Rhododendron fruticosa shrub land, Salix cupularis fruticosa shrub land, Dasiphoru fruticosa shrub land, Polygonum grassland, Grass steppe, Swamp grassland and Kobresia grassland were selected to be experimental samples. The soil fungi were isolated by PDA, PSA, Maize Powder Media and Rose Bengal Medium, which were analyzed by ITS rDNA sequence analysis phenotype identification. According to the identificated fungi, the characteristics of each measure index and types of sampling data, the fungi diversity were analyzed by ecology-evaluating methods. The DGGE and Nested PCR were used to study the fungi diversity; The biological characteristics of three Mortierella were study, which were seclected from dominated fungi, the main results were as follows:1 The quantity of soil fungi were determined in the different incubation conditions, the same sample have different species and quantities in different pH, temperature and media different incubation conditions, Rose Bengal Medium could get more species and quantities than PDA?PSA and corn powders, which was suitable for isolating fungi from soil. By comparing, the optimal incubation temperature, pH and respectively were 20?, 6.5 and Rose Bengal Medium, respectively.2 The soil fungi were classfied by ITS rDNA sequence analysis and phenotype identification, through large-scale isolation methord, Synthetic ITS rDNA sequence analysis and phenotype identification, the following cultured fungi in the alpine grassland of Eastern Qilian Mountains can be drawn: Mortierella spp., Doratomyces spp., Leptosphaeria spp., Cladosporium spp., Verticillium spp., Mucor spp., Tolypocladium spp., Beauveria spp., Hypocrea spp., Truncatella spp., Cordyceps spp., Trichoderma spp., Nectria spp., Didymella spp., Penicillium spp., Bionectria spp., Alternaria spp., Aspergillus spp., Geomyces spp., Fusarium spp., Scopulariopsis spp. and Phaeosphaeria spp. The strains belong to 22 genera, most of them belong to imperfect fungi and zygomycetes. In addition, more than 10 % fungi strains could not clarify the taxonomic status temporarily, which might be new species.3 The diversity and Ecological Characteristics of cultured soil fungi. Species abundance (S), Shannon-Wiener index (H), Simpson dominance index (D) and Pielou evenness index (J) range were 15-18, 2.47-2.81, 0.89-0.93, 0.91-0.97, respectively. Each index fluctuated slowly, and revealed a similar pattern. The Shannon-Wiener index was: Kobresia grassland> Polygonum grassland> Dasiphoru fruticosa shrub land> Salix cupularis fruticosa shrub land> Grass grassland> Rhododendron fruticosa shrub land> Swamp grassland. Except for Pielou index, the others index relatively high in Kobresia grassland and relatively low in Swamp grassland; The results indicate that the diversity of soil fungi were very abundant in the alpine grassland of Eastern Qilian Mountains, and there exist close corelation between fungal diversity and grassland types.4 DGGE analysis of rDNA in 4 types soil fungi, Nested PCR amplification of the ITS1 rDNA, under DGGE optimized condition, soil fungi community structure were analyzed by sequencing and phylogenetic analysis. The results showed, Nested- PCR has high sensitivity, ITS1 rDNA were amplified from micro amounts of nucleic acids, which was about 250 bp in length. The DGGE band sequencing and mapping analysis demonstrated that the DGGE band has big difference in quantity and brightness, and it has same trend as the cultured soil fungi in 4 types grassland.5 The biological characteristics of three Mortierella alpina isolated from alpine grassland in the Eastern Qilian mountains were discussed. The results showed that there were significant differences on their biological characteristics.The optimum nitrogen sources of three M. alpina was Peptone, while the optimum carbon sources of M.alpina 27 was Starch, the optimum carbon sources of M. alpina 60 was Sucros and Gcose was the optimum carbon sources of M.alpina 9. The suitable growth temperature for three M.alpinas was 5?30?and the optimum of M.alpina 27 was 30?, while that for M.alpina 60 and 9 was 5?. All of them can grow at pH 4?9 and pH 7 was the optimum .