欧美杨对PM_(2.5)中重金属铅的吸附、吸收及适应性变化  

Adhesion and absorption of Pb in PM_(2.5) and adaptative changes in Populus euramericana ‘Neva'

作　　者：曹学慧[1] 安海龙[1] 刘庆倩 刘超[1] 郭惠红[1] 尹伟伦[1] 夏新莉[1] 

机构地区：[1]北京林业大学生物科学与技术学院,北京100083

出　　处：《生态学杂志》2015年第12期3382-3390,共9页Chinese Journal of Ecology

基　　金：国家林业公益性行业科研专项(201304301)资助

摘　　要：针对PM2.5中重金属铅污染的日益加重问题,本文利用气溶胶发生系统模拟PM2.5含铅颗粒的发生,研究欧美杨107(Populus euramericana‘Neva’)叶片在不同浓度含铅颗粒物污染处理下对铅的吸附、吸收和转运,以及叶片气孔和相应生理指标的变化。结果表明:欧美杨叶片表面能够吸附含铅颗粒物,重度污染处理的叶片吸附的颗粒物数量多于轻度污染处理。2种铅污染浓度处理的欧美杨均是叶片中的铅含量最高,茎和根中的铅含量较少。但不同污染处理下叶中的铅向茎和根中的运输存在差异。轻度污染处理第3天时,叶中的铅仅运输至茎部,到第7天时运输至根,而在重度污染处理的第3天,叶中的铅已运输至根部。超微结构观察显示,叶片表皮细胞中的铅仅在细胞壁中出现,通过质外体向内运输至叶肉细胞,而叶肉细胞中的铅主要分布在细胞壁和细胞质,液泡中有少量分布。2种污染浓度处理后,随处理时间的延长,欧美杨叶片气孔的开度变小,叶片中的丙二醛(MDA)和脯氨酸(Pro)含量逐渐升高以及超氧化物歧化酶(SOD)活性逐渐增强。研究表明,欧美杨叶片具有吸附、吸收PM2.5中铅的能力,同时通过降低气孔开度、渗透调节、提高抗氧化能力等生理过程来应对大气中的铅污染。Lead （Pb） pollution caused by PM2.5 is becoming increasingly serious. In this study, PM2.5 particles were generated by aerosol generator to simulate different Pb pollution levels. The adhesion, absorption and transportation of PM2.5-Pb by leaves of Populus euramericana ＇ Neva＇ seedlings were studied. The changes of stomata and physiological characteristics in P. euramerica- na leaves were also investigated. The results showed that Pb-containing particles can be adhered by the leaves, and the number of Pb-containing particles on leaves was higher under the severe than the low pollution treatment. The content of Pb was the highest in leaves, while lower in stems and roots under both the low and severe pollution treatments. However, there were some differences in the transportations of Pb from leaves to stems and roots between the two treatments. In the low pollution treatment, Pb was transported from leaves to stems and roots 3 and 7 days af- ter the treatment, respectively. By contrast, Pb in leaves was transported to roots only 3 days af- ter the severe pollution treatment. Ultramicroscopic observation indicated that Pb-containing parti- cles first appeared in the cell wall of leaf epidermal ceils, and was then transported to mesophyll ceils through apoplast. In the mesophyll ceils, Pb-containing particles were mainly distributed in cell wall and cytoplasm, with a few particles observed in vacuole. The stomatal aperture, MDA and proline content, and SOD activity in P. euramericana leaves exhibited adaptive changes with the extension of time under both low and severe Pb pollution treatments. Our results demonstrate that Pb in PM2.5 particles could be adhered and absorbed by the leaves of P. euramericana, and P. euramericana can adapt to Pb pollution through decreasing stomatal aperture, osmotic adjust- ment and increasing oxidation resistance.

关 键 词：欧美杨 PM2.5 铅 吸附 吸收 超微结构 生理特性 

分 类 号：X513[环境科学与工程—环境工程] S792.11[农业科学—林木遗传育种]