The rhizospheric niche of seedlings of Populus ussruiensis colonized by arbuscular mycorrhizal (AM) fungi

Through systemic study on the rhizospheric niche of seedlings inoculated with arbuscular mycorrhizal (AM) fungi, we found that the niche of the host-plant was affected vitally by AM fungi. The selected four AM fungi Glomus mosseae, G. intraradices, G. sinuosa, G. versiforme infected the potted seedlings of Populus ussruiensis and formed mycorrhizal compound with the host plant. Glomus mosseae and G. intraradices have better infection rate than the others. Their infection rates were 64.4%, 67.4%, respectively. The biomass of seedlings infected by the two AM fungi were 2.59, 2.13 times of control, respectively. AM fungi don抰 affect on microbial populations in rhizospheric soil, but increase the number of bacteria, actinomycetes and azotobacter in the root surface and root surround area. AM fungi accelerated the activities of phosphatase, urease, and proteinase in soil rhizosphere, and the activities of these enzymes were positively correlated with the infection rate of AM fungi. AM fungi decreased the pH value of rhizosphere, but the pH value is correlated with the infection rate of AM fungi negatively. The nutrient gathering of available N and P in the rhizosphere of the seedlings inoculated with AM fungi was found, and it was correlated with the infection rate of AM fungi remarkably.