Species Diversity And Ecological Adaptablity Of Arbuscular Mycorrhizal Fungi Of Ammopiptanthus Mongolicus-associated Plants

Because of the abominable climate condition in the northwest desert zones of China, the vegetation is sparse, the plant species composition and community structure are simple. People reclaim land blindly maked the degree of desertification intensified. To improve the desert natural vegetation is the most effective way to control desertification. Ammopiptanthus mongolicus(Leguminosae) is the only endangered broadleaf evergreen shrub endemic to the deserts of northwest China. A. mongolicus and its associated plants undergo competition inhibition and cooperative evolution. Their root systems are developed, with strong cold resistance, drought tolerance and other characteristics, which is thought to be the ideal plants to prevent windstorms and fastens sand in the land. AM(arbuscular mycorrhiza) fungi and the vast majority of vascular plant root can form mutual benefit symbionts. AM fungi played an important role in plant mineral nutrition, moisture absorption and biological mutual role. The glomalin in soil remediation effect has an important role.In this research, we collected soil and root samples from three different sites in Dengkou, Wuhai, and Alxa in the Inner Mongolian desert, in July 2013 and July 2015. We systemically studied on the AM fungal community composition, ecological distribution and relationship with soil factors, and compared with the related research of A. mongolicus. In order to fully provide the basis for the full use of AM fungi resources and biotechnology to promote the vegetative restoration and ecological improvement projects. The main results as follows:1. A total of 25 AM fungal species belonging to 4 genera were isolated from the soil under A. mongolicus-associated plants. Of these fungi, 14 species belong to Glomus, 7 to Acaulospora, 3 to Funneliformis, and 1 to Scutellospora.2. The genera and species of AM fungal community had obvious spatial heterogeneity in three sites and the ecological adaptability is different. Glomus and Acaulospora were the common dominated genera. G. reticulatum was the dominant species. A. bireticulata, G. fasciculatum, G. glomerulatum and G. viscosum were the common subdominants. AM fungi species decreased with increasing soil depth. G. reticulatum and G. glomerulatum were the common dominated species in different soil layers. G. maculosum only appeared in 10-20 cm soil layer of Wuhai.3. The species diversity of AM fungi had obvious temporal and spatial heterogeneity in three sites. Simpson index and evenness index were no significant difference between the sample sites; Species richness and Shannon-Weine index in Alax were significantly higher than those in other sites. Evenness index in 2013 was significantly higher than those in 2015.4. The associated plant roots and AM fungi can form intermediate type arbuscular mycorrhizas. The total colonization was up to 71.38%, and the average spores density reached 74.33/20 g. A. mongolicus-associated plants can form well symbionts with AM fungi.5. AM fungi had obvious temporal and spatial distribution. Hypha colonization, total colonization and spore density in 2013 were significantly higher than 2015. Alax's spore density was significantly higher than Dengkou and wuhai. The maximal value of colonization and spore density were observed at the 0-30 cm shallow soil layer.6. AM fungal species diversity index was closely related to soil factors. Hyphal colonization, spore density and species diversity index were positively correlated with organic C, available N and GRSP. Available P was negatively correlated with species diversity index.7. The average T-GRSP content of the soil was 7.32 mg·g-1, and accounted for 57.60% of soil organic carbon content. GRSP is an important source and component of soil organic C. GRSP was significantly positive correlated with organic C. It showed that GRSP played an important role in the degradation of ecosystems.8. Principal component analysis showed that organic C, available N, available P, acid phosphatase and GRSP were the main influence factors, and can be used to determine the nutritional status of the soil of the Inner Mongolian desert.