北京大学及周边地区非取暖期植物叶片中的多环芳烃

采集了北京大学校园内及周边交通干线附近6种植物叶片样品,分别测定了叶蜡和叶组织中的多环芳烃含量,同步测定了叶蜡、叶脂、气孔密度等参数,藉以探讨机动车尾气排放对植物叶蜡和叶组织中多环芳烃含量的影响.结果证实:交通干线附近样品叶蜡和叶组织中多环芳烃含量显著高于校园对照.叶蜡中多环芳烃含量较叶组织高1～2个量级.叶蜡和叶组织中16种多环芳烃化合物分布谱相似,但高环化合物更多在叶蜡中聚集,而低环多环芳烃在叶组织中占优.叶蜡多环芳烃含量与单位叶面积中的叶蜡含量成反比,叶组织多环芳烃含量与气孔密度成反比.

Polycyclic Aromatic Hydrocarbons in Plant Leaves from Peking University Campus and Nearby in Summer Season

Leaves of 6 plants were collected from two sites on and around Peking University campus in summer season of 2003. PAHs in the leaf-wax and tissues were determined simultaneously with leaf-wax content, tissue lipid, specific surface, and stomata density. The results were compared to investigate the possible sources of PAHs in the leaves. For both leaf-wax and tissue samples, levels of PAHs depended on plant species and were lower in the samples from campus than those from outside of campus in short distance to busy traffic, suggesting a significant influence of vehicle emission. The concentrations of PAHs in leaf-wax were 1-2 orders of magnitude higher than those in leaf tissues. While the PAH profiles in the leaf-wax and leaf tissues were similar in general, the relative contents of volatile compounds were higher in the tissues than in the wax. Negative correlations were identified between PAHs concentration in the leaf-wax and the wax content and between the tissue PAH content and stomata density.