四川人工桉树林中的巨桉、尾叶桉、兰桉、大叶桉有外生菌根、内生菌根和混合菌根 3种菌根类型 ,而窿缘桉缺少混合菌根类型。自然状态下 ,5种桉树菌根化率有明显差异 ,其中以巨桉、兰桉最高 ,分别为 6 8 3 %、6 4 6 % ,而窿缘桉菌根化率最低 (2 9 6 % )。同一桉树树种 ,外生菌根化率最高 ,内生菌根化率次之 ,混合菌根化率最低。林分郁闭度对菌根真菌的分布有很大影响 ,随着森林郁闭度增加 ,桉树林分外生、内生菌根真菌的类群趋于复杂 Eucalyptus grandis, Eucalyptus urophylla, Eucalyptus urophylla and Eucalyptus grandis had three kinds of mycorrhizal ectomycorrhizal fungi, endomycorrhizal fungi and mixed mycorrhizal fungi in Sichuan Artificial Eucalyptus forest, while the mixed eucalyptus species lacked the mixed mycorrhiza. Under natural conditions, there were significant differences in mycorrhizal rates among the five eucalyptus species, of which E. grandis and E. grandis were the highest (68.3% and 64.6%, respectively), whereas the eucalyptus root colonization rate was the lowest (2.96% ). The same eucalyptus species, the highest ectomycorrhizal rate, followed by the rate of endogenous mycorrhizal, mixed mycorrhizal rate lowest. Forest canopy density has a great impact on the distribution of mycorrhizal fungi, with the forest canopy density increased, eucalyptus forest exogenous species of endomycorrhizal fungi tend to be complex