Abstract: Using BIOLOG microplate technique, the microbial diversity in root zone soils of Acacia confusa and Eucalyptus urophylla polluted by heavy metals in Guishan of Huangpu area (Guangzhou) were studied. The results show that the soil of Guishan in Huangpu area is mainly polluted by total Cd and Zn, which have the badly negative influence on soil microbial community. The worse soil condition reduces bacterial amounts, delays microbial metabolic activity, lowers microbial carbohydrates and amino acides utilization and reduces microbial diversity indexes. Bacterial amounts and Microbial diversity in root zone soils are higher than soils without plant. However, because of the heavy metal pollution in Huangpu area, the bacterial amounts, microbial substrate utilization patterns and diversity indexes in the root zone soils of Acacia confusa show no significant difference with that of Eucalyptus urophylla. While, at the late stage of incubation, microbial metabolic activity in the root zone soils of Acacia confusa increases sharply and has higher metabolic capability than other soil samples. Moreover, Acacia confusa can not only stabilize the Cu and Pb in soil, but also absorb Cd and Zn. And its nitrogen fixation can enhance soil nutrients. Therefore, Acacia confusa, a popular pioneer tree in Guangzhou, is suitable for the vegetation rebuilding in the heavy metals polluted site in Huangpu area, Guangzhou.

Key words: root zone soil, microbial community diversity, Acacia confusa, Eucalyptus urophylla , heavy metal pollution, root zone soil, microbial community diversity, Acacia confusa, Eucalyptus urophylla