兰州市10种常用园林绿化树种叶表面微结构对其滞尘量的影响

Influence of leaf surface microstructure of ten commonly-used landscaping tree species on dust retention in Lanzhou City

【目的】探讨园林植物叶表面微结构对滞尘量的影响。【方法】以兰州市西固工业区10种园林绿化植物叶片为供试材料,采用称重法测定单位叶面积滞留颗粒物总量(total suspended particulates,TSP)、PM10、PM2.5的量,采用扫描电镜获取叶表面微结构影像,对叶片滞尘能力与叶表面微结构的关系进行了定量分析。【结果】10种园林绿化植物单位叶面积滞留量存在显著性差异(P<0.05),TSP、PM10和PM2.5滞留量的变化区间分别为0.90~2.92、0.11~0.32和0.11~0.31 g/m^(2);10种绿化植物中单位面积滞尘量最多的是紫叶矮樱(Prunus×cisterna),其次是紫叶李(Prunus cerasifera)和榆叶梅(Amygdalus triloba),滞尘量最小的为银杏(Ginkgo biloba)、丁香(Syringa oblata)、五角枫(Acermono Maxim)等;PM10、PM2.5的滞留量与气孔密度、气孔个数呈极显著正相关(P<0.01),与气孔开度呈显著正相关(P<0.05),与沟槽宽度、形状系数呈显著负相关(P<0.01);叶面微结构特征指标排序为气孔宽度>形状系数>气孔长度>气孔面积>气孔个数>气孔密度>沟槽宽度>气孔开度。【结论】植物叶表面微结构特征是影响植物吸附与滞留大气中细颗粒物量的重要因素之一,其中气孔宽度、形状系数、气孔长度和气孔面积对滞留细小颗粒物量影响较大。

【Objective】The objective of this study was to investigate the influence of leaf microstructure on the amount of dust retention in garden plants.【Method】Ten landscaping trees in industry area of Xigu district of Lanzhou city were employed as the materials.The amount of TSP(total amount of residual par⁃ticulate matter),PM10 and PM2.5 per leaf area was measured by the method of weighing,and microstructure images of leaf surface were obtained by scanning electron microscopy,followed by quantitative analysis on the relationship between leaf dust retention capacity and leaf surface microstructure.【Result】There were significant differences in the amount of dust retention per leaf area among ten kinds of landscaping plants(P<0.05).The variation ranges of TSP,PM10 and PM2.5 were 0.90~2.92,0.11~0.32 and 0.11~0.31 g/m^(2).Among the 10 sampled plants,Prunus×cisterna had the largest amount of dust per unit area,fol⁃lowed by Prunus cerasifera and Amygdalus triloba,and Ginkgo biloba,Syringa oblata and Acermono Maxim had the smallest amount of dust retention.The retention amount of PM10 and PM2.5 was highly sig⁃nificantly positively correlated with stomatal density and stomatal number(P<0.01),and was significantly positively correlated with stomatal opening(P<0.05),and significantly negatively correlated with groove width and shape coefficient(P<0.01).The leaf microstructure characteristics ranged with the order as fol⁃lowing:stomatal width>shape coefficient>stomatal length>stomatal area>number of stomatal pores>stomatal density>groove width>stomatal opening.【Conclusion】The microstructure characteristics of plant leaf surface is one of important factors affecting the amount of fine particulate matter adsorbed and retained from atmosphere,among which the stomatal width,shape coefficient,stomatal length and stomatal area generate a great influence on the amount of fine particulate matter.