Abstract:Six strains of ectomycorrhizal fungi of Mongol Scotch Pine (Pinus sylvestris var.mongolica Litvin) were obtained through field collecting,isolating,purifying and man-made inoculation experiments two strains,and the laboratory introduced from France which have a wide host range and Cenococcum geophilum of bacteria as the research object.Thirty days emergence seedlings of Mongol Scotch Pine were inoculated by ectomycorrhizal fungi strains using method of root soaking with different types of bacteria agent of ectomycorrhizal fungi in the field.The effects of different single fungus strains on promoting the growth of Mongol Scotch Pine were studied.The results showed that:(1)Five local strains and one France strain in this experiment can promote the growth of Mongol Scotch Pine seedlings.The results of inoculation show that the seedlings inoculated strains best on height,10.5%～111.4% more than control after inoculated 130 days;collar diameter 4.55%～92.8% more than control after inoculated 130 days;the dry weight of seedlings inoculated strains are 6.8%～184.5% more than control after inoculated 130 days.(2)Mycorrhizal biotechnology can raise the resistance to drought of Mongol Scotch Pine seedlings:under the condition of water stress,the chlorophyll content increased in leaf by 5.82%～36.92%;net photosynthesis rate amplified by 3.84%~230.72%,the time of leaf wilting up delayed to 10.3～25 h,the time of seedlings Critical lethal time delayed to 13.8～38.2 h.(3)Seedlings inoculated by strain G-S.g,S.g,the average height,collar diameter,infection rated,dry weight and enhance the drought resistance of seedlings were increased significantly.To sum up,strain G-S.g and strain S.g should be fine strains to seedlings of Mongol Scotch Pine.In conclusion,strain G-S.g and strain G-S.g of ectomycorrhizal fungi solid microbial inoculum can be put in use in promoting the growth of Mongol Scotch Pine seedlings.We concluded that inoculation with EM fungi in chestnut plant can enhance thedrought resistance.