Survey On The Diversities Of Arbuscular Mycorrhizal (AM) Fungi And Its Host Plants In Wetlands Of Beijing Area

Wetland resources are plentiful in China, and they play more and more roles in human production and lives. Wetland plants are used more and more in city landscaping, artificial wetland, disposal of domestic sewage, etc. Biological components have important function in wetland and attract much attention. Arbuscular mycorrhizal (AM) fungi and its host plants are important components in wetland, however, it is little known how they exist and distribute in wetland, and what the related effect factors are. Beijing area possesses plentiful wetland resources. With increasing urbanization level, wetland plants play more and more roles in landscaping, treatment of domestic sewage, improvement of eco-environment, etc. In this study, the main wetlands in Beijing area are selected to investigate the diversities of AM fungi and its host plants, and to discuss the possible factors affecting AM formation in wetland plants. The results will provide reference for the exploitation and utilization of biological resources in wetlands of Beijing area.Firstly, we took and determined samples of water, sediment and plants from 13 wetlands, such as Shahe Reservoir, Nanhaizi Wetland, the Olympic Forest Park Wetland, etc. According to these results, we selected Nanhaizi Wetland and the Olympic Forest Park Wetland as the main objectives to investigate further the effects of season and annual shift on diversity of AM fungi and its host plants. The main results as followed:(1) In total, there were 315 plants that were taken from 68 sites, and they belong to 32 family,49 genus and 56 species. These plants included ferns (1 family,1 genus and 2 species), monocotyledon (11 family,25 genus and 29 species) and dicotyledon (20 family,23 genus and 25 species). Among of them,92.8% plants (52 species) have AM structure. Reed (Phragmitesaustralis) and cattail (Typha latifola) are the most common plants with AM structure in Beijing area, since they existed in more than 50% sampling sites.(2) The results of morphological identification and molecular biological analysis of AM fungi spore indicated that Glomus and Acaulospora were the dominant species, and the followed species were Diversispora and Gigaspora. Species diversity and similarity of AM fungi showed significant difference among various sampling sites. The similarity of AM fungi in rhizosphere of various plants also showed significant difference that was between 20% and 80%.(3)Physical and chemical properties of sediment, especially the con centrations of NH4+-N, TDP and TOC, not only decreased diversity of A M fungi but also reduced the dominance of dominant AM fungi.Moreov er,the diversity of AM fungi was higher in spring than in autumn.(4) Mycorrhizal colonization rate was less affected by hydrological regime but was much affected by the physical and chemical properties of sediment. High PO43-, TDP in water and TDP in sediment decreased mycorrhizal colonization rate. On the contrary, TOC in sediment had positive effect on the formation of AM structure in wetland plants. Mycorrhizal colonization rate showed difference among seasons.