The Distribution Of Arbuscular Mycorrhizal Fungi And Dark Septate Endophytes Of Saibei Desert Plant And Study Of Isolation And Culture Of DSE

AM( arbuscular mycorrhizal) fungi are soil fungus which can form symbiotic associations with the majority of terrestrial plant species. The fungus can enhance the ability of uptaking nutrients of roots, thereby enhance the host’s resistance of drought and saline.Dark septate endophyte( DSE) is a ubiquitous group of soil fungi that can extensive colonizative in plant-root cell cortex even vascular tissue, and form melanized septate hypha.The wide ecological distribution of DSE and the positive role under the extreme environment, which have important application value in the aspects of vegetation restoration and ecological reconstruction.Salix psammophila and Caragana korshinskii in Saibei desert steppe as the object to study the colonization status of dark septate endophytes( DSE) and arbuscular mycorrhizal( AM) fungi. On the basis, DSE strains were isolated from S.psammophila and C.korshinskii and the classification and identification based on the method of morphology and molecular biology, then, analysed the chemical composition of the DSE strains. The purpose was to provide a theoretical basis that make full use of AM and DSE fungi resources to promoted adapting, the extreme environment for desert plants and ecological reconstruction. The results were as follows:1. This study indicated that S.psammophila formed typical symbiotic relationship with AM fungi and the total colonization of AM fungi was 69%. Tempto-spatial distribution of AM fungi has certain regularity; the highest total colonization appeared in the 0~20cm soil depth and increase gradually as the sampling time delay. The total colonization of AM fungi among sites showed:Yuan Shangdu > Qing Geletu, The colonization in 2014 was below in 2013 between the interannual.2. We could find in this study that S.psammophila and C.korshinskii could form typical fungal-root structure with DSE and the average total colonization was 83% and 45%,respectively. The total colonization of DSE had no evident trend in soil layers, but display significant variation as the sampling time delay. Between years, the result was differ in different sites. Between the two plants showed that S.psammophila colonization is higher than C.korshinskii.3. The colonization of AM and DSE fungi was closely related to soil factors. Totalcolonization of AM fungi was positive correlations with soil humidity, p H, alkaline phosphatase and EEG. Total colonization of DSE were positive correlations with soil humidity, and negative correlations with soil humidity, available nitrogen, organic matter, acid phosphatase, alkaline phosphatase and EEG. Soil humidity, p H, alkaline phosphatase and easily extractable glomalin were the main factors in desert environment.4. The study showed that AM and DSE fungi simultaneously infected in the same root segment, and the colonization rates between the two plants showed that significant or extremely significant negative correlation.5. The DSE separated from S.psammophila were 35 strains, including 23 strains of Qing Geletu, 12 strains of Yuan Shangdu. By morphological and molecular biology methods to identify, these strains were divided into five various kinds, which respectively was Curvularia australiensis 、 Alternaria alternata 、 Paraphoma chrysanthemicola 、 Bipolaris maydis 、Cochliobolus miyabeanus. C.australiensis was the common species in two sample plots. The DSE separated from C.korshinskii were 13 strains, including 10 strains of Qing Gele, 3 strains of Yuan Shangdu.We identified two various kinds, which were Ascomycota sp. and Cladosporium tenuissimum. C.tenuissimum was the common specie of the two sample sites,whicn could be isolated in two sample plots.respectively.6. Among the pure culture strains of DSE of S.psammophila, the melanin content, total protein content and polysaccharide content of P.chrysanthemicola showed maximum value in Qing Geletu. But the metal elements content, P.chrysanthemicola, B.maydis and C.australiensis had no significant difference. The maximum values of chemical components content are concentrated in C.australiensis in Yuan Shangdu. The components content of C.australiensis in different sampling sites showed: Yuan Shangdu>Qing Geletu.7. Among the pure culture strains of DSE of C.korshinskii in Qing Geletu, The melanin content, total protein content and polysaccharide content were showed C.tenuissimum bigger than Ascomycota sp.. The difference between the two species of metal elements content was not significant. Between the two plants, the chemical components content of C.tenuissimum showed: Yuan Shangdu>Qing Geletu.