Study On Arbuscular Mycorrhizal Fungi And Dark Septate Endophytic Of Artemisia Argyi In Inner Mongolia

Artemisia argyi belongs to Artemisia of Compositae.It can adapt to poor soil conditions.Large-scale planting can not only help farmers increase income,but also protect the ecological environment.Arbuscular Mycorrhizal fungi(AMF)and Dark Septate Endophyte(DSE)can form symbiotic structures with plant roots under natural conditions and improve the ability of host plants to absorb water and nutrients.In this experiment,the roots and rhizosphere soil of A.argyi were collected in farmland,riverside,sand land and town parks in Ordos and Tongliao.The colonization of AMF and DSE in the roots of A.argyi and their correlation with soil properties were analyzed.Species composition,ecological distribution and diversity of AM fungi in the rhizosphere soil of A.argyi in different habitats were investigated.The DSE of A.argyi roots were isolated by traditional fungal isolation and culture method,and the species identification was carried out by molecular biology method.The microbial flora(AMF,DSE and growth-promoting bacteria)were artificially assembled and the plant growth-promoting effect was verified.The results were as follows:1.The roots of A.argyi were highly infected and colonized by AMF and DSE and formed typical structures in four habitats in two regions,the infection situation had spatial difference(p<0.05).It was greatly influenced by soil physical and chemical properties.Through correlation analysis,it was found that the infection rates of AM vesicles and clumps of A.argyi roots were significantly correlated with the contents of available nitrogen and available phosphorus in soil.The formation of microsclerotia structure of DSE was positively correlated with the content of soil acid phosphatase,total nitrogen,available nitrogen and alkaline phosphatase.There was a significant positive correlation between DSE infection intensity and total phosphorus content in soil.2.The amount of soil culturable bacteria,fungi and actinomycetes in 4habitats in 2 regions was significantly correlated with the contents of available nitrogen,the infection rates of AM vesicles and DSE microsclerotia respectively.3.In this study,a total of 5 genera and 18 species of AM fungi were identified,8 species belonged to Glomus,6 species belonged to Acaulospora,2 species belonged to Claroideoglomus,1 species belonged to Scutellaspora and 1 species belonged to Diversispora.Except for river sides,the dominant AM fungi in the rhizosphere of A.argyi were G.melanosporum and A.bireticulata in Ordos.4.The diversities of AM fungi were closely related to soil physical and chemical properties and soil nutrients directly restrict the colonization of AM fungi.AM spores densities were positively correlated with soil available phosphorus contents,actinomycetes numbers and infection rates of clumps,AMF species abundance were positively correlated with total nitrogen contents,acid phosphatase contents,soil fungi numbers and vesicle infection rates,Shannon Weiner indexes were positively correlated with soil total nitrogen contents and vesicle infection rates.All soil properties affected the diversities of AM fungi.5.11 DSE species belonging to 4 genera were isolated from A.argyi roots by traditional culture method.Two DSE strains with high isolation frequency(Paraphoma chrysanthemicola and Curvularia tsudae),AMF and growth-promoting bacteria were selected for artificial combination,and their growth-promoting effects on A.argyi were studied.Single inoculation of two DSE strains significantly increased the underground dry weight and the number of primary lateral roots of A.argyi,the growth promoting effect of inoculation of P.chrysanthemicola was better than that of inoculation of C.tsudae.When DSE,AMF and growth-promoting bacteria were mixed inoculated,the number of primary lateral roots and the root-shoot ratios of A.argyi were higher than average level.When AM and growth-promoting bacteria were mixed,the stem diameters of A.argyi were higher than the average level.When DSE were mixed with growth-promoting bacteria,the aboveground dryweight and root-shoot ratios of A.argyi were higher,but the stem diameters were lower than the average level.When DSE and AMF were mixed,the seedlings heights,primary lateral roots numbers and underground dryweight of A.argyi were higher than the average level,the biomass of A.argyi reached the highest and the growth promotion effect was the best.