Soil Characteristics And Root-associated Fungi In Roots Of Pinus Sylvestris Var.mongolica Plantation In The Hulunbuir Sandy Land

Pinus sylvestris var.Mongolia is one of the most important tree species in farmland shelterbelt in North China,but it has serious decline problem.Soil,fungi and plants are closely related,and endophytic fungi are important media for plants to absorb nutrients,and play an important role in the growth of P.sylvestris.In this study,P.sylvestris plantation and natural forest were used in Hulunbuir sandy land of middle age,near mature and mature age groups By using the method of field investigation,indoor analysis and molecular biology,the soil physical and chemical and enzyme activities of P.sylvestris forest were measured and analyzed,and the characteristics of the fungal community structure and functional groups in the roots were explored.The purpose of this study was to explore the soil physical and chemical and enzyme activities of P.sylvestris forest,and on the fungal community and functional groups in the roots,its response to environmental factors provide theoretical basis for the management of P.sylvestris plantation.The main results show that:(1)The contents of soil moisture,available phosphorus and available potassium of P.sylvestris forest were the highest in the near mature forest,but the soil nutrient content was not effectively accumulated in the mature forest.The results showed that the activities of four enzymes were the lowest in the near mature forest;the invertase activity was the lowest in the natural forest,and the urease activity was the highest in the natural forest,and the soil nitrogen cycling effect was better in the natural forest;urease,phosphatase and invertase were significantly correlated with soil moisture content,but catalase had no significant correlation with soil physical and chemical properties.(2)A total of 520 OTUs were obtained from the root tip samples of P.sylvestris in Hulunbeier sandy land,belonging to 197 genera,87 families and 5 phyla.The relative abundance of Basidiomycota and Ascomycota were 54.98% and 39.27%,respectively.Alpha diversity index was the smallest in mature forest and the largest in middle age forest.The Pielou evenness index of root fungi in mature forest was significantly lower than that in other forest ages(P<0.05),and the distribution proportion of fungal community in mature forest was unbalanced;the correlation between basidiomycetes and soil organic matter and urease was strong;the correlation between Boletus and catalase,invertase and available phosphorus was strong.(3)The proportion of symbiotic vegetative fungi were dominant in the root fungi of P.sylvestris in sandy land,and the relative abundance of them was the largest in mature forest,and the proportion of symbiotic vegetative fungi in natural forest was close to that in natural forest;some fungi had different ecological strategies in different stands,and showed more ecological strategies in natural forest;relative abundance of pathotrophic fungi was related to soil total phosphorus and soil p H There was a significant positive correlation between saprophytic fungi and soil organic matter(P<0.05),but there was no significant correlation between symbiotic vegetative fungi and soil characteristics.