Abstract:Response of three woody species (native Symplocos lancifolia and Aporosa chinensis, and exotic Eucalyptus exserta) to air pollution grown at two experimental sites, Wuxing with ceramic factories nearby at Foshan city (WX) and control site at South China Botanical Garden (BG), was examined physiologically. Buffering capacity of S. lancifolia and A. chinensis was higher than that of E. exserta. pH in cell sap of leaves of three species was lower in WX than that in BG. After the leaves were treated with 10 mmol L-1 NaHSO3 under 20.5μmol m-2s-1 light intensity for 10 h, the photosynthetic oxygen evolution, Fv/Fm, Fv/Fo and ΦPSⅡ in all the three species decreased to some extent, most significant decrease in three parameters was found in E. exserta. The results demonstrated that there was less resistance to air pollution in E. exserta than in the other two, and it was consistent with different buffering capacity of cell sap in three species. It is suggested that the buffering capacity of cell sap in plant leaves can be a useful index in evaluating the resistance of plants to SO2 pollution.