Species Diversity And Ecological Adaptablity Of Arbuscular Mycorrhizal Fungi Of Legume Plant In Saibei Desert Steppe

Saibei desert steppe is a typical desertification area in northern China.It has spatial heterogeneity and multifarious ecological environment.The frequently blown-sandactivity makes the region formed a lot of wind erosion and desertification land. In desert areas, there live lots of legume plants including Caragana korshinskii that is non-clonal plant and Hedysarum laeve that is cloning plant, which are not only the dominant species in desert areas, but have a higher economic value and ecological value. In this research, two kinds of legume plants in the Saibei deser were based on the background and the target plant. The symbiotic relationship between AM fungi and two kinds of legume plants were used as an entry point, we not only systemically studied on the AM fungal community composition, ecological distribution and relationship with soil factors of two kinds of legume plants, but also studied on the diversity of arbuscular-mycorrhizal fungi of legume guerilla clonal plants which can invade open patches through clonal growth. In order to enrich the AM fungal germ plasm resource,to provide materials and basis for strengthening effect of clonal plants in ecological restoration and re-construction. Results were shown as follows:Abundant diversity of AM fungi was found in the rhizosphere of leguminous plants in Saibei desert steppe. 21 AM fungal species belonging to four genera were isolated from soil samples of Caragana korshinskii. Ten species belonged to Glomus, seven species belonged to Acaulospora, three species belonged to Funneliformis, one species belonged to Scutellospora. three genera and 17 species of AM fungi were isolated and identified from the rhizosphere of Hedysarum laeve, nine species belonged to Glomus, seven species belonged to Acaulospora,one species belonged to Funneliformis.Species diversity of AM fungi of two legume plants have seasonal variations. Species richness, Shannon-Weiner index and evenness of AM fungi in Caragana korshinskii and Hedysarum laeve in August and October were significantly higher than in June. In the same sample sites, there has difference in species composition of AM fungi because of different host plants. Spore morphology of two kinds of host plants were obvious difference, which had the xeric structure characteristics of deep color and small size.The root of C. korshinskii and H. laeve could form strong symbiotic relationship with AM fungi,which formed Arum-type arbuscular mycorrhiza and intermediate-type arbuscular mycorrhiza, respectively. Arbuscular mycorrhizal fungi have distinct temporal and spatial heterogeneity. Total colonization of C. korshinskii is top-slope > mid-slope > foot-slope, Total colonization of Hedysarum laeve is mid-slope>top-slope> foot-slope. With the time delay, AM fungal colonization rate of C. korshinskii and H. laeve decreased than in 2013; but the spore density of two kinds of leguminous plants are basically the same, showed an upward trend.Correlation analysis and principal component analysis showed that C. korshinskii and H. laeve were significantly correlated with soil factors. The acid phosphatase, total Glomalin, available nitrogen, alkaline phosphatase, organic carbon were the main factor affecting the C. korshinskii soil, Available phosphorus, available potassium, organic carbon, urease, p H were the main factor affecting of H. laeve affecting soil nutrient status.Easily extractable Glomalin of C. korshinskii and H. laeve reached maximum value at the foot-slope. Glomalin was significantly positive correlation with organic carbon and available nitrogen. The percentage with soil organic carbon and nitrogen was the same as the changes of glomalin. but all are much greater than C. korshinskii.It proved Glomalin had an important contribution to soil nutrient dynamics, carbon and nitrogen cycle.Different growth periods of H. laeve invade open patches through clonal growth, making the AM structure of the fungal symbiontic colonization rate and soil physical and chemical properties changed significantly. The maximum total colonization of AM fungi occurs at florescence period. The number of invaded community is different, which invaded community in flowers fall period is more than other periods and all immersed in plots. The invasion of clonal plants significantly increased the content of soil available nutrition, such as organic carbon, available nitrogen and phosphatase, which became more suitable for the growth of clonal plants.