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作 者 ：彭钢,田大伦*,闫文德,朱凡,梁小翠

期 刊 ：生态学报 2010年 30卷 14期 页码：3700~3706

关键词：多环芳烃；气孔密度；气孔长宽比；叶片宽长比；叶面积；

Keywords:Polycyclic Aromatic Hydrocarbons (PAHs), stomatal density, stomatal length:width ratio, leaf width:length ratio, leaf area, urban street tree species,

摘 要 ：用气质联用仪测定了长沙市樟树（Cinnamomu camphora）、广玉兰（Magnolia grandiflora）、桂花（Opsmanthus fragrans）和红檵木（Redrlowered loropetalum）4个主要绿化树种叶片中PAHs含量，同时测定了叶片的气孔密度、气孔长宽比、叶片的宽长比和叶面积等叶面结构特征值，探讨了叶面结构与叶片中PAHs含量的关系。结果表明：红檵木叶片的PAHs含量最高，为11.13mg?kg-1,16种PAHs在4树种叶片中均有不同程度的检出，其中以3环和4环为主，菲的浓度最高。除桂花外，在气温较低的秋冬季节，其余3种植物叶片气孔密度大PAHs含量高。叶面宽长比、气孔长宽比均与叶片PAHs含量呈极显著正相关，而叶面积与PAHs含量呈极显著负相关。表明叶面结构是影响叶片PAHs含量的重要因素。研究结果可为城市绿化树种合理选择与配置提供科学依据。

Abstract:Polycyclic Aromatic Hydrocarbons (PAHs) are a large group of chemicals that mainly produced by incomplete combustion of coal, gasoline, wood, garbage or other organic materials. PAHs consist of a number of toxic compounds which have great harmful effects on plants, animals and human health. It has been commonly recognized that trees have great potential for the scavenging, storage and purification of relatively large amounts of PAHs. Accumulation of PAHs in vegetation depends on the properties of the particular PAHs as well as on the properties of the accumulating surface. However, while most research focused on accumulation capacity of trees on PAHs, less know the relationship between PHAs concentration and leaf surface structure. In order to examine the relationship between accumulation of PAHs and leaves′ structure of major tree species in southern China, the composition and accumulation of PAHs in leaves of four major urban street tree species (Cinnamomu camphora, Magnolia grandiflora, Opsmanthus fragrans and Redrlowered loropetalum) were investigated in Changsha city, Hunan province, China. Structural features of the leaves, including leaf stomatal density, stomatal length:width ratio, leaf width:length ratio, and leaf area, were also measured. The objectives of the research were to (1) determine the composition and concentration of PAHs in leaves of the selected four tree species, (2) examine the relationship between PAHs concentration and surface structures of leaves of the four urban street tree species, and (3) compare the accumulation capacity of PAHs among the four tree species The results showed that all 16 priority PAHs were detected in the leaves of the four tree species, but the three-ring and four-ringf PAHs dominated, in particular for Phe. The highest total concentration of PAHs (11.13mg?kg-1) was found in the leaves of Redrlowered loropetalum while the lowest (3.66mg?kg-1) in the leaves of Opsmanthus fragrans. Total PAHs concentrations were 7.58 mg?kg-1 and 4.34 mg?kg-1 in the leaves of Cinnamomu camphora and Magnolia grandiflora, respectively. Except the tree species of Opsmanthus fragrans, a closely relationship between leaf stomatal density and accumulation of PAHs was found in other three tree species′ leaves. Because of low temperatures in fall and winter seasons, higher leaf stomatal density resulted in higher accumulation of PAHs in leaves. There were significant positive correlations between leaf stomatal length:width ratio, leaf width:length ratio and PAHs concentration in leaves of all test tree species. But a negative correlation was found between leaf area and PAHs concentrations in leaves. Our results indicated that structural characteristics of leaves of urban tree species were important factors in affecting the accumulation of PAHs in study area.

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