Ecological And Physiological Research On VA Mycorrhizas Of Populus Ussuriensis

By the field investigation for the VA mycorrhizal resources of Populus ussuriensis, the results show that P. ussuriensis is one of VA mycorrhizal tree species, and the spores of VA mycorrhizas are screened from the soil of rhizosphere in different forest age. There are 3 genera and 7 species, Glomus mossea, G. intraradicex, G. geosporum, Acaulospora melles, Scutellospora dipurpurascens, respectively.We succeed in artificial inoculation for seedling of P. ussuriensis by use of 5 VA mycorrhizal fungi including Glomus mossea, G. intraradicex, G. versiforme, G. mossea93, G. sinuosa. And we found that the infection ratio of different fungi for seedlings have a positive correlation with growth effect. And then the process of infection of G. intraradicex and G. mossea for seedlings are observed.The establishment of symbiosis relation for P. ussuriensis seedlings and VA mycorrhizal intensifies leaf photosynthesis, increases chlorophyll content, enhances the activities of calalase and nitratase, promotes the development of roots system, which not only increases the absorbing area of roots, but also enlarges the rate of actively absorbing area of root system, intensifies the polyphenol oxidase activity. During the period of the seedlings infected by VA mycorrhizal fungi, the soluble sugar, nutritive elements (N, P, K), endogenous hormones (IAA, GA3, ZR, ABA) of host roots, shoots (leaf), and peroxidase of roots shows a dynamic change, and material distribution and energy utilization in tree seedlings are regulated effectively, which play a very important role in process promoting accelerating healthy and rapid growth of seedlings.VA mycorrhizas increases the richness of species and quantity of rhizosphere microbe, makes micro-ecological structure more stable, intensifies the activities of phosphatase, urease, and proteinase of soil, and makes nutrient elements in rhizosphere rich during the period of the tree seedlings infected by VA mycorrhizas fungi.VA mycorrhizas of P. ussuriensis have a good absorption for insoluble phosphor and nitrate nitrogen, the growth promotion of the seedlings for different fungi under different forms and gradient of fertility have a significant difference, and the infection rate of mycorrhizas are controlled by fertility level.P. ussuriensis seedlings mixed with Amorpha fruticosa are inoculated by VA mycorrhizal fungi could make P. ussuriensis rhizosphere nutrient enrichment.