高级检索

    北京市16种树木吸附大气颗粒物的差异及颗粒物研究

    Differences in atmospheric particle accumulation on leaf surface in sixteen tree species in Beijing and characteristics of particles.

    • 摘要: 为选择吸附颗粒物能力强的绿化树种修复大气颗粒物污染,以北京市西直门交通枢纽的16种常见绿化树种为材料,利用扫描电镜观察叶片表面的微观形貌和颗粒物的形态,并用ImageJ软件对颗粒物的粒径分布进行统计。研究发现,16种树叶表面形貌差异较大,阔叶树种叶片上表面形态比较复杂,有沟槽、褶皱、绒毛和蜡质等,下表面主要有气孔、腺毛、绒毛等,形态相对较单一。针叶树种叶表面形态相对简单,有少量褶皱,但是叶表面分泌大量油脂。叶片表面附着的大部分颗粒物表面粗糙且形态不规则,粒径小于2.5 μm的颗粒物在3种粒径中占比最大。通过扫描电镜X射线能谱仪对颗粒物的元素进行分析发现,组成颗粒物的元素主要有C、N、O、Si、Ca、Fe,及少量的Na、Mg、Pb、Ni、Cd和Pd等元素。从颗粒物来源分析,主要含有C、N、O、Na、Mg、Si和Ca等元素的颗粒物,可能主要来自自然界,而Pb、Fe、Ni、Cd和Pd等元素含量较高的颗粒物可能主要来自人类活动的产物。叶表面颗粒物附着密度结果表明,圆柏和油松较其他树种叶片颗粒附着密度大,其余较大的树种依次是栾树、国槐和榆叶梅等。研究结果为揭示树木吸收大气颗粒物的机制及合理选择园林绿化树种提供了重要的理论科学依据。

       

      Abstract: In order to select plant species that can efficiently adsorb atmospheric particles in air pollution, microstructures of leaf surface and morphology of particles on leaf surface of 16 urban tree species were observed by using scanning electron microscopy (SEM) and size fractions of particles were analyzed with Image J software in Xizhimen transportation hub of Beijing. The results showed that: 1) there were marked differences in leaf surface morphology. The morphology of the upper side of leaves of broad-leaved tree species was rather complex, containing grooves, folds, fluffs, waxes, etc. In contrast, the morphology of the lower side of the leaves was relatively simple, mainly including stomas, glandular hairs and fluffs. The leaf surface of conifers had a few folds and a lot of secretion. 2) Most of particles were rough and irregular. 3) Particles (2.5 μm) accounted for the largest proportion. The result of elementary components analysis indicated that leaf-accumulated particles were mainly comprised of C, N, O, Si, Ca, Fe and few Na, mg, Pb, Ni, Cd and Pb. The particles including mainly C, N,O, Na, Mg,Si and Ca might come from natural source, whereas particles containing Pb, Fe, Ni, Cd and Pd might be the result of human activity from diesel, coal and other anthropogenic sources. Comparing particle adhesion density on leaf surface of the 16 tree species, Sabina chinensis, Pinus tabuliformis, Koelreuteria paniculata, Sophora japonica and Amygdalus triloba were efficient in capturing particles on leaf surface. The study can provide scientific theories to reveal how trees absorb particles and thereby choose efficient greening tree species.

       

    /

    返回文章
    返回