| Arbuscular mycorrhizal fungi ( AMF ) is extremely widespread in the nature distribution ,not only is the main constituent of soil microbial communities, moreover can form the symbiotic system with the overwhelming majority higher plant, has many beneficial physiologies and the ecology effects to the plant growth .AMF plays an important role in the evolution and distribution of host plant, such as the maintain of biological diversity. The leguminous plants have developed roots, strong resistance, rapid growth ,biological nitrogen fixation and other characteristics, especially the leguminous plants can affect together with the root nodule bacteria and the AMF forms the root nodule and arbuscular mycorrhizal and this kind of synergy symbiotic superiority enable the leguminous plants become he vanguard plants in China's western desert region, and play an vital role in the ecological environment construction.Maowusu sandland ,ecosystem serious degradation, the climate arearid,is the key area of northwest China about ecological environment construction . In order to thoroughly discusses the leguminous plants rhizosphere AMF distribution and the activity, we choose Melilotus suaveolens ,Leapedeza bicolor and Astragalus adsurgens and such as 12 kind of leguminous plants in the differentsample sites in Maowusu sandland ,in May, July, September,2006,opening exhibition about the colonization and diversity of AMF from leguminous plants with soil factors, wish can offer the material and basis to degenerate ecosystem restoration and there construction provides .Main research results are as follows:1.The experiment separate 41 AMF species of 4 genera,10 belong to Acaulospora,3 belong to Gigasporn, 24 belong to Glomus, 4 belong to Scutellospora among them; including 10 uncertain species .2 The diversity of AMF in rhizosphere of leguminous plants from Maowusu sandland was rich. The rhizosphere of Leapedeza bicolor Turcz. has 16 species which was the richest; Sophora alopecuroides and Thermopsis lanceolat R.Br. only has 7 species,was the poorest. Different plant category inside, Glomus is dominant genera, the next in order is Acaulospora, Scutellospora and Gigaspora are lower.3.The average colonization is up to 64.78 % of 12 kinds of leguminous plants,and spore density in rhizosphere soil of 12 kinds of leguminous plants equally reaches 4.37 /g soil, expressing that muti~symbiosis is very common between leguminous plants and AM fungi, and both have grown stronger closely.4.The richest sopre density 9.26/g soil was found in Alhagi pseudalhagi Desv.rhizosphere;the poorest sopre density 0.69 /g soil was found in Astragalus adsurgens Pall. rhizosphere.In spring, summer and fall, summer(July) has the highest AM fungal colonization rate and spore density. The AM fungal colonization and spore density has no correlation.5 The AM fungal colonization rate was obvious different in 12 kinds of leguminous plants Glycyrrhiza uralensis Fisch. has the highest colonization and Thermopsis lanceolat R.Br. has the lowest colonization. Besides, the result shows that different structural of AM fungal hanv different colonization, hyphae colonization>vebuscular colonization> abuscular colonization.; versicular and hyphae colonization are far higher than arbuscular; the abuscular colonization only has few obvious different in rhizosphere of all 12 kinds of leguminous plants6.The AM fungal colonization and spore density was influenced by soil factors, host plants and season changes. In the Maowusu sandland soil nutrient conditions,soil available N, soil available K , soil organic matter and soil PH has the positive correlation with AM fungi colonization and spore density; only soil Available P has negative correlation.7 Sampling depth also has obvious influence for AM fungal colonization rate and spore density, and the highest Numerical also be found in 0-20cm soil layer, which With the increase of soil depth showed a downward trend8 AM fungal colonization rate and spore density was different in different regions of Maowusu sandland, General trend as AM fungal colonization rate Inner Mongoliaï¹¥Shaanxiï¹¥Ningxia, spore density Inner Mongoliaï¹¥Ningxiaï¹¥Shaanxi.9 The total AM fungi colonization rate and spore density in different host plant rhizosphere's change has with soil layer changes agreed with soil layer, for example, in three sample plants, Alhagi pseudalhagi Desv.shows the greatest AM fungal colonization and spore density in every soil layer ,such as 0-10cm,10-20cm,20-30cm and 30-40cm... |
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