Tolerance and Purification Capacity of Some Species of Trees against Sulfur Dioxide
重庆某些树种对SO2的耐性和净化能力的研究

In order to determine the threshold doses of acute and chronic injury by SO2, the saplings fumigated with SO2 in the open top chamber were conducted. According to "the principle that purification capacity of SO2 by trees is in a function of sulfur intensity accumulated in leaves and its transfer rale out of leaves, the purification capacity of a tree can be estimated in varied sulfur contents in the leaves before and after fumigation. The experimental results show that the trees Cuninghamia lanceolate, Camptotheca acuminata, Cinnamomum plylyphylum possess strong tolerance and higher purification capacity against SO2, but the capacity of Robinia pscudoa-cacia etc are lower. Chongqing is a city with heavier SO2 pollution, so the said trees can be selected for gre-ening around the urban districts.