Differences in quantity and composition of leaf particulate matter and morphological structures in three evergreen trees and their association in Harbin, China
Differences in quantity and composition of leaf particulate matter and morphological structures in three evergreen trees and their association in Harbin, China
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哈尔滨市三种常绿乔木叶片颗粒物数量、组成及形态结构的差异及其关联
DOI：
10.1016/j.envpol.2019.06.124
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发表时间：
2019
影响因子：
8.9
通讯作者：
Wang Shurui
中科院分区：
文献类型：
--
作者：
Xu Haijun;Wang Wenjie;Wang Huimei;Sun Yufeng;Zhong Zhaoliang;Wang Shurui
城市树木被认为可以有效地净化大气颗粒物，但物种间的差异尚未得到很好的定义，特别是PM的化学组成。以3种常绿树种（杜松、黑松和云杉）叶片表面和蜡质层PM为研究对象，采用X射线衍射、X射线光电子能谱、傅里叶变换红外光谱和电感耦合等离子体发射光谱等方法，研究了3种常绿树种叶片表面和蜡质层PM的吸附特性及其组成特征。PM去除的可能改善也进行了评估，详细的全市树木普查和不同的情况下的物种调整数据。我们发现：1）圆柏叶上的PM量为5.73 g m−2，是黑松和云杉的2-2.5倍（p< 0.05）。其中，蜡层中分别占38.73%、38.22%和23.11%。2)与PM数量的显式种间差异相比，更复杂的种间差异对不同的组成性状表现出不同的模式。总体而言，叶表PM中O、Si、Al、Fe、N、Pb、Cu、Ni、Cr和Cd含量较高，而蜡质PM中C和Na含量较高（p< 0.05）。3)关联排序发现，叶片越小、含水量越低、单位质量叶面积越大、蜡质含量越高、气孔开度越大，叶片对PM的吸附量越大，PM中C双键、O、Si、Al、N、Pb、Cu、Ni、Cr、Cd等重金属含量也越高。4)与其他两种树种相比，城市森林中杜松比例的增加更能有效地去除大气中的PM，同时也能更好地去除PM中的重金属，但减少了PM中的结晶矿物。我们的研究结果表明，在城市绿化中，适当的物种配置可以最大限度地提高空气PM的去除能力。
Urban trees have been assumed to effectively clean air particulate matter (PM), while the inter-species differences are not yet well defined, especially the PM chemical composition. In this study, PM from leaf surface and wax layer of 3 evergreen tree species (Juniper:Juniperus rigida; Black pine:Pinustabuliformisvar.mukdeais; Spruce:Picea koraiensis) were used for finding differences in PM adsorption and its compositional traits (characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectrum and Inductively coupled plasma-optical emission spectrometry). Possible improvement in PM removal was also evaluated by a detail whole city tree census and different scenarios of species adjustment data. We found that: 1) the amount of PM on juniper leaves was 5.73 g m−2, 2–2.5-fold higher than black pine and spruce (p< 0.05). Of them, 38.73%, 38.22%, and 23.11% were in the wax layer. 2) Compared with the explicit interspecies differences in PM quantity, more complex interspecies difference showed different patterns for different compositional traits. In general, leaf surface PM had higher O, Si, Al, Fe, N, Pb, Cu, Ni, Cr, and Cd, while the wax PM had higher C and Na contents (p< 0.05). 3) Association ordination found that the smaller leaf size, lower leaf water content, higher leaf area per unit mass, higher wax content, and larger stomatal openness aligned with the more PM adsorption by leaf, together with the higher amounts of Cdouble bondO stretching, O, Si, Al, N, heavy metals of Pb, Cu, Ni, Cr, and Cd in PM. 4) Compared with the other 2 species, increase of juniper percentage in urban forests is more effective for maximizing PM removal from air, accompanying more heavy metal removal but less crystalized minerals in PM. Our findings highlight that proper species configuration in urban afforestation could maximize the air PM removal capacity.