The Response Of Typical Quercus Forest Soil Fungi And Ectomycorrhizal Fungi To Environment Factors And Cd Pollution

Soil is a complex and dynamic ecosystem, in which biological process is mostly governed by microorganisms. Microorganisms play critical roles in nutrient cycling, maintenance of soil structure, degradation of agrochemicals, and the control of plant and animal pests. The forest soil is characterized with higher acidity by comparison with agricultural soil. Due to the special ecological environment, forest soil is favorable to fungal growth and has more rich fungal species. We selected Liaoning typical successional temperature Quercus mongolica forest(20, 30 and 40 years of natural secondary forest), the single stable forest ecosystem, to study the responses of forest soil fungi to forest ecosystem development. In addition, we studied the response of Quercus acutissima seeding and soil fungi/ectomycorrhizal fungi to Cd stress in typical Q. acutissima forest soil by the lab cultivation. These results of this study will provide scientific basis for the protection and utilization of Quercus forest fungi and ectomycorrhizal fungi. Major results are listed as follows:(1). After the Illumina Miseq pyrosequencing of soil and roots in three sucessional Q. mongolica forest the total observed fugal phylotypes were 508 and among them 328 fungal phylotypes were Ascomycota and 135 were Bsdidiomycota. Other phyla including Chytridiomycota, Glomeromycota, and Zygomycota were rarely presented.(2). Forest age of three sucessional stands had great effect on fungal communities. The fungal phylotypes accounted for 81%, 71% and 76% of the total taxa numbers in 20 years, 30 years and 40 years stands, respectively. A total of 93 ectomycorrhizal fungal phylotypes were identified. In the 20 years stand, Cortinarius, Hydnellum and Tomentella were more abundant, whereas Russula and Sebacina were more abundant in the 40 years stand. The most representative fungal phylotype of 30 years stand was Lachnum in Ascomycota phylum. The soil physicochemical properties were closely related to the diversity and abundance of fungi. The ammonium nitrogen, nitrogen and soil organic carbon was positively correlated with diversity and abundance, while pH, water content, total phosphorus and available phosphorus were the opposite.(3). After the Illumina Miseq pyrosequencing of Q. acutissima soil and root, 331 fugal phylotypes were observed and among them 208 fungal phylotypes were Ascomycota(62.8%) and 96 were Bsdidiomycota(29%). Other phyla including Chytridiomycota, Glomeromycota, and Zygomycota were rarely presented. In addition, a total of 93 ectomycorrhizal fungal phylotypes were identified.(4). The Q. acutissima seedlings grow well under the Cd concentration of 40 mg kg-1. The seedling height did not reduce significantly and the dry weight of stem was improved. Therefore, Q. acutissima could be considered as a means to efficiently improve reforestation processes. The addition of benomyl affected the characteristics of plant by reducing the enzyme activities and the absorption of 15 N under the higher Cd dosage, especially reducing the mycorrhizal colonization. In addition, the benomyl had reduced fungal abundance and diversity except for Scleroderma at 40 mg Cd kg-1. Cd altered the fungal community structure in soil and roots, which improved the fungal diversity and abundance at lower dosage and the abundance of Gibellula and Scleroderma at higher dosage. However, the higher dosage of Cd reduced the other fungal diversity and abundance. Gibellula and Scleroderma can be used as plant inoculants to repair Cd polluted soil.