攀援植物对大气颗粒物的吸附作用

The Deposition of Particulate Matters on Climbing Plant

植物通过叶片对颗粒物的吸附作用能够有效降低大气中颗粒物的浓度.用攀援植物进行绿化是城市绿化的重要手段,五叶地锦（Parthenocissus quinquefolia）作为中国北方地区常见的攀援绿化植物,研究其对大气颗粒物的吸附效果能够为降低大气中颗粒物浓度、改善环境质量、优化绿化方法提供一定依据.选取道路旁和校园内两处采样地点,距地表不同采样高度对五叶地锦叶片进行采样,使用扫描电镜和软件相结合的方式,对叶表面吸附的颗粒物进行计数,对颗粒物进行粒径分级,通过X 射线能谱仪对叶表面吸附颗粒物的元素组成和颗粒物特征进行分析.结果表明：五叶地锦能够有效吸附不同粒径的大气颗粒物,对粒径在0.2~2.5 μm 的细颗粒物吸附数量占总吸附颗粒物数量的90%以上.颗粒物粒径越小,吸附在叶表面的数量越多.叶片上、下表面由于叶表面形态特征的不同,对吸附颗粒物数量有影响,五叶地锦叶片上表面对不同粒径范围的颗粒物吸附数量均明显高于下表面.道路旁2.5 m 高度处叶表面上细颗粒物密度为8.4×106/cm^2,校园内2.5m 高度处叶表面上细颗粒物密度为5.2×106/cm^2.环境对植物吸附颗粒物的数量有明显影响.叶表面吸附的颗粒物的组成元素受环境影响,道路叶片上吸附颗粒物元素组成中Si、Ca、Fe 含量高.文章所采用的方法对植物叶片吸附颗粒物数量和元素组成的分析能够直观地反映出植物在减缓大气污染、减少PM2.5 等颗粒物上所起到的作用.

Numerous studies have demonstrated that the plants can purify particulate matters (PM) by absorbing atmospheric pollutants, and may significantly impact air quality. Climbing plants are widely used in urban greening, and Parthenocissus quinquefolia is a common climbing greening plant in northern China. It is meaningful to study P.thomson’ ability on PM accumulating in order to reduce PM concentration in the atmosphere, improve environment quality and optimize greening method. In this study, leaves of P.thomsoniare collected from two places, near a traffic road and in a campus, and three heights from the ground. A scanning electron microscope (SEM) and energy dispersive X-ray (EDS) is used to count the quantity of particles which are accumulated on leaf surface and analyze the elements of particles. The results shows, P.thomsonican accumulate particulate matters (PM) effectively, especially for fine particles (0.2~2.5μm) in quantitative terms. The percentage of fine PM accumulation in total PM is more than 90%. The smaller the particle’s size is, the larger quantity accumulates on leaf surface. The upper side of the leaf accumulated more PM than the underside, because the two sides’ microstructures are different. At 2.5 m height, the density of fine PM on leaf surface is 8.4×106/cm2 near a road, and it is 5.2×106/cm2 in campus. The samples from the road collected more PM than the ones from the campus.The elements found on the leaves affected by the environment, the ratio of elements were different between the two sampling sites. There are more Si, Ca and Feobserved on leaves near the road. The method in this paper could intuitively reflect the plant’s influence on reducing atmosphere pollution and accumulating particles.