Effect Of Inhanced UV-B Radiation On The Diversity Of Arbuscular Mycorrhizal Fungi In Alpine Meadow Soil Ecosystem

Arbuscular mycorrhizal fungi (AMF) which have a wide distribution in nature, can form arbuscular mycorrhiza (AM) symbiosis with most of the terrestrial plants. AMF can enhanced the nutrient absorption and the capacity of the anti-adversity for plants, improve the soil structure, affect the plant diversity of terrestrial ecosystem, structure of the plant community and ecosystem productivity and stability.In this study, the primary researchment on the AMF species diversity of alpine meadow soil ecosystem under the long-term increased UV-B radiation was done. The AMF spores were separated and identified through water sieve method and microscopic inspection of stained technique. The main results showed:1. Spores density decreased with the increasing of the depth of the soil under the radiation of UV-B. The spores density in surface soil and next layer soil had a significant difference with the control group.2. Fourteen species arbuscular mycorrhizal fungi were separated from the alpine meadow soil ecosystem, in which seven were identified. They belonged to five genus: Glomus, Scutellospora, Acaulospora, Entrophospora and Ambispora. The Glomus was the dominant genus in this ecosystem; however, Ambispora was a new one and had never been reported before.3. Long-term increased UV-B radiation altered the community structure and diversity of AMF in the soil. Two species in Glomus and one in Acaulospora were absent in the treatment group of UV-B radiation whereas Entrophospora infrequens was present only in the treatment group.4. The content of total P and available P in the soil decreased significantly under the radiation of long-term increased UV-B, while total N, total C and soil organic carbon accumulated indistinctively.5. In surface soil, the spores density had a very significant negative correlation with available P and significant negative correlation with total P. And in the second layer, it also showed a significant negative correlation between the spores density and the element P. However, in the third layer, there was no significant correlation between the spores density and the soil properties.