冬季苏北8种常绿乔木吸滞颗粒物能力与叶表微结构关系

The Relationship between the Adsorption Capacity of 8 Evergreen Arbors in Northern Jiangsu Province and the Micro Structure of Leaf Surface

以冬季苏北地区8种常绿乔木(枇杷、石楠、龙柏、桂花、广玉兰、雪松、大叶女贞、香樟)为对象,采用水洗-滤膜法测定叶片对不同粒径颗粒物(PM、PM_(>10)、PM_(2.5~10)、PM_(2.5))吸滞量,并用S-3000N型扫描电镜观察叶表微结构特征。结果表明,8种常绿乔木单位叶面积的PM、PM_(>10)、PM_(2.5~10)、PM_(2.5)吸滞量分别为0.5531~3.8396、0.4683~3.4867、0.0631~0.2558、0.0218~0.1810 g·m^(-2);PM_(>10)、PM_(2.5~10)、PM_(2.5)吸滞量分别占PM质量的85.68%、9.22%、5.10%;叶片有多条线状突起,皱褶较多,气孔较密集的枇杷、石楠、龙柏单位叶面积滞留颗粒物能力较强;叶面光滑平整的大叶女贞、香樟吸滞颗粒物能力较弱;叶面有较厚蜡质层、沟壑较少、气孔密集的雪松对粒径越小的颗粒物吸滞能力表现越优;沟壑投影面积增大能显著提高叶片对不同粒径颗粒物的吸滞量;保卫细胞面积与PM和PM_(>10)吸滞量呈极显著正相关;气孔密度与PM_(2.5~10)和PM_(2.5)吸滞量呈极显著正相关;沟壑投影面积、保卫细胞面积、气孔密度等叶片微结构是调控冬季8种常绿乔木叶片颗粒物吸滞能力的主要因素。

Eight evergreen arbors(Eriobotrya japonica,Photinia serrulata,Sabina chinensis,Osmanthus fragrans,Magnolia grandiflora,Cedrus deodara,Ligustrum lucidum,and Cinnamomum camphora)occurring in Northern Jiangsu Province in winter were selected as research objects.The leaf adsorption capacity to particulate matter with different sizes(PM,PM_(>10),PM_(2.5-10),PM_(2.5))was measured via water washing-membrane filtering method.The microstructures of the leaves were observed by the scanning electron microscope.The results suggested that the ranges of the absorption capacity of the leaves of 8 evergreen arbors to PM,PM_(>10),PM_(2.5-10) and PM_(2.5) per leaf area were 0.5531-3.8396,0.4683-3.4867,0.0631-0.2558,and 0.0218-0.1810 g·m^(-2),respectively.The absorption capacity of the leaves to PM_(>10),PM_(2.5-10) and PM_(2.5) by weight accounted for 85.68%,9.22% and 5.10% of the total PM,respectively.E.japonica,P.serrulata,S.chinensis leaves,which had multiple linear protrusions,more wrinkles,and dense stoma had relatively stronger adsorption capacity to particulate matter and L.lucidum,and C.camphora leaves with smooth and flat surface had relatively weaker adsorption capacity to particulate matter.C.deodara leaf surface featured by thick waxy layer,less furrows,and the dense pores displayed better performance in adsorbing stagnant particles with smaller particle size.The increase in gully projection area could significantly improve the adsorption capacity of particles in different sizes.The stomatal guard cell area of the leaves was extremely,significantly,positively correlated with PM and PM_(>10) adsorption and stomatal density was extremely significantly,and positively correlated with PM_(2.5-10) and PM_(2.5) adsorption.The microstructures of the leaves such as the gully projection area,the guard cell area and the stomatal density were the main factors that control the particulate matter adsorption capacity of the leaves of 8 evergreen arbors in winter.