典型木本植物叶片与大气汞的交换通量及其影响因素研究

项目名称： 典型木本植物叶片与大气汞的交换通量及其影响因素研究

项目编号： No.41303072

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 天文学、地球科学

项目作者： 牛振川

作者单位： 中国科学院城市环境研究所

项目金额： 25万元

中文摘要： 大气汞收支不平衡的问题使森林植被在汞循环中的重要作用日益凸现，植物叶片与大气汞(简称叶汞)的交换通量是估算其作用的基础；然而，叶汞复杂的双向交换过程及其影响因素尚未得到较好的阐明。本项目针对木本植物叶汞交换过程及其影响因素认识的不足，以典型阔叶树苗(南方常绿杨树和小叶榕)和针叶树苗(马尾松和杉木)为研究对象，拟通过动态通量袋法，在智能温室内从叶片尺度上观测叶汞交换通量的水平和变化趋势，比较阔叶树种和针叶树种叶汞交换通量的差异；分析叶片生理、环境因素和大气汞浓度对叶汞交换通量的影响，并确立每种植物叶汞交换通量的补偿点；阐明叶汞交换的气孔过程和非气孔过程及其影响因素。本项目的开展将有助于科学地认识森林植被与大气汞的交换规律及其在大气汞收支中的作用，为制定全球大气汞的减排政策提供参考。

中文关键词： 大气汞；叶片；木本植物；通量；影响因素

英文摘要： The estimated mercury (Hg) emissions to the atmosphere are significantly greater than the known sinks, resulting in the mass unbalance for atmospheric Hg, and the role of forests in Hg biogeochemical cycle has attracted more and more attentions. The Hg exchange flux between foliage and the atmosphere is the foundation for understanding the role of forests in Hg cycle. However, it is not well elucidated the dynamic bi-directional exchange processes of Hg between foliages and the atmosphere, and the governing factors. This project intends to carry out the following research activities on the seedlings of two typical broadleaf trees (Populus deltoides×P. nigra cv. Chile, Ficus microcarpa var. pusillifolia,) and two coniferous trees (Pinus massoniana Lamb, Cunninghamia lanceolata (Lamb.) Hook) in controlled chambers. 1. Observe the levels and variations of foliar Hg fluxes through a dynamic flux bag, and compare the differences of foliar Hg fluxes between the broadleaf and coniferous woody plants. 2. Analyze the influence of foliar physiological activities, environmental factors and atmospheric Hg concentrations on foliar Hg fluxes, and find out the compensation points of foliar Hg fluxes for each plant. 3. Distinguish the stomatal processes from the nonstomatal processes of foliar Hg exchange fluxes, and uncover th

英文关键词： atmospheric mercury；foliages；wood plants；flux；factors