Diversity And Ecological Distribution Of Arbuscular Mycorrhizal Association In The Grassland And Desert Of Inner Mongolia

Arbuscular mycorrhizal fungi (AMF) are important microorganisms in natural ecosystem. There are distribution differences of AMF because of the vegetation types and the environmental factors. Arbuscular mycorrhizas (AM) are the most widespread symbiotic association that formed between plant roots and the AMF. Because of its potential influence on ecosystem processes, the role in determining plant diversity in natural communities and the ability of the arbuscular mycorrhizal fungi to induce a wide variety of growth responses in coexisting plant species, the research on AM has been given much attention. In this paper, we studied the diversity, richness and relative abundance of AMF species and mycorrhizal plant species in the grassland and desert of Inner Mongolia. A total of 162 plant species from the grassland and desert of Inner Mongolia were collected and examined, in which 131 species (80.86%) were infected with arbuscular mycorrhizal fungi (AMF). Most species of the Gramineae, Compositae, Leguminosae, and Liliaceae are infected with the AMF. The dominant species of plant community have high a colonization rate that differs among the plant species. Endangered plant species, Tetraena Mongolic, Ammopiptanthus mongolicus, Helianthemum soongoricum and Potaninia mongolica are all mycorrhizal plants. Co-symbiosis is very common between the AMF with azotobacter and Frankia in the same host plant. We find that two Carex species were infected with AMF but just have some vesicles. The study also indicates that the diversity of mycorrhizal plants in grassland is higher than in desert. Arum- and Paris-type symbioses are the two main morphological types of arbuscular mycorrhizas. Most wild plant species in this survey belong to Arum-type mycorrhizas, and only 20 plant species belong to Paris-type. A few plants have the intermediate type. All of the Allium species form the Arum-type mycorrhizas, but the Lilium pumilum form the Paris-type that has distinctive intracellular hyphal swellings. The results show that the plant largely controls the AM morphological structure type. There was no significant correlation between mycorrhizal structure types with life forms and colonization rates, neither with root types of host plants.The wild Allium species are more important to study the biodiversity of the AMF in ecosystem, Inner Mongolia.36 AMF species of 5 genera were identified including 11 uncertain species in Acaulospora, Gigaspora, Glomus and Entrophospora from the grassland and desert. Two new record species in China and 5 unrecorded species were obtained from the survey areas. There are differences of AMF diversity and its occurrence following the gradient of vegetation and community. The richness of the AMF species and the density of the AMF spores in the grassland are higher than that in the desert or sand. Glomus and Acaulospora are dominant genera. The results from the analysis of the different sample soils show that the frequency of occurrence of the genus Glomus was the highest, even higher than the Acaulospora that is the second most abundant genus. Some special species occur in the water meadow.Geographical and environmental factors affect the diversity and distribution patterns of AMF. The major factors include the water, temperature and soil components. There is significant correlation between both the spore density and the species richness, along with the pH value of the soil and the available phosphates and the organic matter in soil.The results show that some changes of species richness and spores density of AMF occurred in grazing area compared with its undergraduate community. The diversity of AMF is lower in artificial ecosystems. This is the first work to study the AMF in grassland and desert of Inner Mongolia. It is significant work to understanding the ecology and functioning of the arbuscular mycorrhizal symbiosis in the ecosystems.