北京市5种典型植物滞尘特征及影响因素

Particulate matter adsorption and the main influencing factors of five typical plants in Beijing

采用室内实验法定量比较北京市5种典型植物(大叶黄杨、月季、榆叶梅、紫薇、五叶地锦)叶片滞留颗粒物以及吸附水溶性离子的能力差异,并从叶表面特征分析差异原因.结果表明,不同植物叶片滞留TSP的能力大小顺序为:五叶地锦>紫薇>榆叶梅>月季>大叶黄杨.滞留PM5—10的能力大小顺序为:月季>榆叶梅>紫薇>大叶黄杨>五叶地锦.滞留PM5的能力大小顺序为:大叶黄杨>月季>紫薇>榆叶梅>五叶地锦.利用离子色谱法等测定颗粒物的化学组分,其主要组分为:有机碳(34.24%)、无机碳(33.45%)、硅(15.43%)、硫酸盐(14.18%)、氯化物(11.75%)、硝酸盐(1.45%),表现出道路环境特征和二次污染特征.在扫描电镜下观察叶表微观结构,发现叶表面有沟槽的五叶地锦和紫薇的滞尘能力较强,叶表气孔密度大的大叶黄杨阻滞细颗粒物能力较强,这从一定程度解释了不同植物阻滞颗粒物能力差异的主要原因.在研究期间内,5种植物叶片上的颗粒物滞留量呈增加趋势.降雨对叶面TSP冲刷作用明显,对PM5—10和PM5的影响较小.

Five typical plants （Buxus megistophylla, Rosa chinensis, Amygdalus triloba, Lagerstroemia indica, Parthenocissus quinquefolia） in Beijing were selected to examine the adsorption ability for particulate matter and soluble ions by quantifying the leaf microstructure. The results showed that adsorption ability for particulate matter was in the order of Parthenocissus quinquefolia 〉 Lagerstroemia indica 〉 Amygdalus triloba 〉 Rosa chinensis 〉 Buxus megistophylla ; for PM5-10 Rosa chinensis 〉 Amygdalus triloba 〉 Lagerstroemia indica 〉 Buxus megistophylla 〉 Parthenocissus quinquefolia; for PM5 Buxus megistophylla 〉 Rosa chinensis 〉 Lagerstroemia indica 〉 Amygdalus triloba 〉 Parthenocissus quinquefolia. Predominant chemical compositions were organic carbon （34.24%）, inorganic carbon （ 33.45%）, silicon （ 15.43%）, sulphate （ 14. 18%）, chloride （11.75%） and nitrate （1.45%） by ion chromatography, illustrating charactersitics of road environment and secondary pollution. Leaf microstructure was observed using scanning electron microscopy. Parthenocissus quinquefolia and Lagerstroemia indica with groove on leaf surface had stronger dust-retention abilities, Buxus megistophylla with high stomatal density had stronger capability of adsorbing fine particulate matters, which explains the differences in the ability of adsorbing particulate matter between trees in a certain extent. During the study period, the particles amounts retained on five plants leaves showed matter on leaf surface significantly, but had little an increasing trend. Rainfall removed particulate influence to PM5-10 and PM5 on leaf surface.