Mycorrhizae Type Associated with Eucalyptus in Sichuan and Effect of Forest Density on Mycorrhizal Fungi

There existed ectmycorrhiza, endomycorrhiza and dual mycorrhiza in Eucalyptus grandis, E.globules, E.urophyus and E.robusta while E.exserta is deficient in dual mycorrhiza in Sichuan. 5 species of Eucalyptus have significant differences in mycorrhiza infection under natural condition, of them, Eucalyptus grandis, E.globules, respectively 68 3%, 64 6%, have the highest mycorrhiza infection rates while E.exserta is the lowest in mycorrhiza infection rates (29 6%). For the same species of Eucalyptus, ectmycorrhiza, endomycorrhiza and dual mycorrhiza respectively rank first, second and third in mycorrhiza infection rates. It is concluded that forest density has the great influence on the distribution of mycorrhizal fungi, and ectmycorrhizal, endomycorrhizal fungi become complex as forest density increases.