北京市9种常见绿化树种吸收积累SO_2能力研究

Sulfur Dioxide Absorption and Accumulation Capacity of 9 Common Urban Greening Tree Species in Beijing

[目的]探究北京市9种常见绿化树种吸收积累SO_2能力,择优筛选净化大气理想树种,为未来北京城区绿化结构调整提供科学依据。[方法]采用BaSO_4比浊法测定北京市9种常见绿化树种在不同污染条件下叶片硫含量,通过计算相对吸硫量并利用平均污染指数法评价其对SO_2的吸收净化能力,比较相互间差异性,筛选出吸收净化SO_2能力强的树种。[结果]表明:(1)不同污染条件下,同种绿化树种叶片硫含量及相对吸硫量普遍存在显著性差异,随着环境污染水平的增强,叶片硫含量和相对吸硫量呈现逐渐增高的趋势;(2)相同污染条件下,不同绿化树种吸收净化SO_2能力普遍存在显著性差异,表现为旱柳吸收能力极强,其平均相对吸硫量2.38 mg·g^(-1),平均污染指数为2.23;国槐吸收能力强,其平均相对吸硫量1.18 mg·g^(-1),平均污染指数为2.09;臭椿、黄栌、毛白杨、色木槭吸收能力中等;榆树、侧柏、油松吸收能力相对较弱。[结论]不同污染环境条件下,同种绿化树种叶片硫含量和相对吸硫量均呈现出随着环境污染水平逐渐的增强而逐渐升高的趋势;而在相同污染环境条件下,不同绿化树种叶片硫含量和相对吸硫量均存在显著性差异。旱柳和国槐可以作为北京市城市绿化用以净化SO_2的理想树种。

[ Objective] To choose the ideal greening species for Beijing by evaluating the sulfur dioxide absorption and accumulation capacity of 9 common urban greening tree Species in Beijing, and to provide scientific basis for structure optimization of urban greening in the future. [ Method] BaSQturbidimetry was used to determine the sul- fur contents in the sample leaves under different pollutant conditions. Then the relative sulfur absorption capacity and average contaminative index were calculated to evaluate the sulfur dioxide absorption and accumulation capaci- ty. By comparing the dissimilarity, the ideal greening species were screened out. [ Result] （ 1 ） There is significant difference in sulfur contents and relative sulfur absorption capacity among species under different pollutant condi- tions. The capacity is positively correlated with the pollution levels. （2） There are obvious differences in sulfur di- oxide absorption and accumulation capacity among the 9 species under same pollutant conditions. It is proved that Salix matsudana is the best （the average relative sulfur absorption capacity is 2.38 mg · g^-1 and the average con- taminative index is 2.23 ） , followed by Sophorajaponica （the average relative sulfur absorption capacity is 1.18 mg·g^-1 and the average contaminative index is 2.09 ）, Ailanthus altissima, Cotinus coggygria, Populus tomentosa and Acer rnono are the medium, and Ulmus pumila , Platycladus orientalis and Pinus tabuliformis are poorer. [ Con-clusion] Salix matsudana and Sophora japonica could be the ideal species tbr urban greening in Beijing.