Ecological research on arbuscular mycorrhizal fungi from the rhizosphere of Caragana korshinskii in the Loess Plateau

Spatial distributions of arbuscular mycorrhizal fungi in the rhizosphere of Caragana korshinskii and its relativity to soil factors were investigated in four natural environments of Yanan，Suide,Hengshan and Yulin in Shaanxi Province.The results show that sampling sites have significant effects on the percentages of colonization of vesicle and arbuscule and the spore density of AM fungi.The highest value of vesicular colonization and spore density are in Suide,and the highest arbuscular colonization is in Yulin.Sampling depth of soil significantly affects the spore density in four sites,the highest spore density appears in 10～20cm soil layer;the highest percentage of colonization of AM fungi occurs at 0～10cm or 20～30cm soil layer.Spore density is positively correlated with vesicular colonization and negatively correlated with arbuscular colonization.Spore density is also negatively correlated with the contents of soil organic matter,soil available P,soil available K and soil Cl^-.Vesicular colonization has a positive correlation to soil pH and a negative correlation to the contents of soil moisture,soil available K and soil Cl^-.Most of AM fungi in the samples belong to Glomus,but a few of species belong to Acaulospora and Scutellospora.The results suggest that the spore density and the extent of vesicular colonization are useful indicators for evaluating the changes of soil environmental ecosystems.