北京7种湿地植物的颗粒物附着能力研究

Particulate Matter Adsorption Capacity of 7 Species of Wetland Plants in Beijing

湿地植物的附着作用是削减大气细颗粒物浓度的有效方式。为了定量研究不同湿地植物附着大气细颗粒物（PM）的能力,选择北京市常见的7种湿地植物芦苇Phragmites australis、香蒲Typha orientalis、水葱Scirpus validus、黄花鸢尾Iris tectorum、茭白Zizania latifolia、凤眼莲Eichhornia crassipes、慈姑Sagittaria sagittifolia,采用水洗测量法测定植物表面颗粒物滞留量及其粒径组成,利用扫描电子显微镜在高真空模式下观察植物表面的结构特征,比较7种湿地植物表面结构特征与单位面积的滞尘量及粒径组成的关系。研究结果表明,（1）不同湿地植物附着颗粒物组分的能力存在差异,凤眼莲和慈姑附着PM、PM_（10）和PM_（2.5）的能力最强。（2）湿地植物表面滞留的PM组分以10-100μm的颗粒物为主,占PM组分的比例为64.2%-87.1%;其次是PM_（2.5-10）,占8.6%-29.5%;PM_（2.5）颗粒物最少,占1.06%-3.92%。（3）湿地植物气孔宽度对植物附着颗粒物的能力起主导作用,气孔宽与PM、PM_（10）和PM_（2.5）附着量分别呈显著的正相关关系（P〈0.05）;植物表面粗糙程度越大、表面结构越复杂,越有利于PM_（2.5）的滞留。该研究精确量化了7种湿地植物附着PM的能力,可为北京市未来的湿地规划建设和合理的湿地植物配置,以及PM_（2.5）调控政策的制定提供依据。

Wetland plant adsorption is effective in reducing the concentration of air particulate matter.This study investigated the capturing capability of air particulate matter（PM） of 7 species of wetland plant（Phragmites australis,Typha orientalis,Scirpus validus,Iris tectorum,Zizania latifolia,Eichhornia crassipes,Sagittaria sagittifolia） in Beijing Hanshiqiao wetland park.The grain size of plant surface particles was determined by water-washing measurement method.The micromorphological structures of plant surface were observed using a scanning electron microscope in high vacuum mode.The relationships between the dust-capturing capability and the micromorphological characteristics of plant surface were compared among the 7 species.The results showed that the PMs absorbed by plant surface varied among different species.The E.crassipes and S.sagittifolia had the strongest capability of capturing PM,PM_（10） and PM_（2.5）,PM_（10-100）,PM_（2.5-10） and PM_（2.5） accounted for 64.2%-87.1%,8.6%-29.5%and 1.06%-3.92%of PM respectively.The stoma width of wetland plants might play a main role in capturing the PMs,as the stoma width was positively related to the absorbed PM,PM_（10） and PM_（2.5）（P〈0.05）.The PM_（2.5） capturing capability might be improved with the roughness and structural complexity of the surface of leaf and stem.This study provide scientific evidence for wetland designing and plant configuration,as well as for making policies of PM_（2.5） pollution control.