樟树叶片示踪高速路附近大气氮沉降

目的]研究维管束植物组织监测大气氮沉降的可行性。方法]在距高速路不同距离的地点采集不同树冠位置的樟树叶片及其下方的根际土壤，按照叶片面积大小对叶片进行分类，用元素分析仪分析叶片和土样所含氮量，统计分析叶片年龄、污染源和树冠对樟树叶片的影响。结果]大叶片氮含量显著低于中叶片和小叶片；叶片氮含量随着离高速路距离的增大逐渐降低，而且差异显著，其与土壤氮含量变化无一致趋势；树冠不同位置氮含量也有差异：树顶叶片氮含量显著高于树底和树沿。这说明在土壤条件不同的情况下，樟树叶片也可以很好地指示大气氮沉降。结论]维管柬植物监测大气环境具有可行性。

Using Camphor Tree Leaf to Trace N Deposition near a Motorway

Objective ] To test the possibility of using vascular plant species to indicate atmosphere N deposition. Method ] The camphor tree leaf and rhizosphere soil at different crown position were collected in sites with difference distance from a motorway. The leaves were classified according to the leaf area and N content in leaf and soil samples were analyzed by element analyzer. The effects of leaf age, pollution sources and tree crown on the leaves of camphor tree were analyzed. Result] N content in old leaf was significantly less than in younger leaf. N con- tent in leaves near the motorway was significantly much more than that at the further sites, but there was no correlation between nitrogen in leaves and in soil. The leaves at the tree top had more N than the others, which indicated that camphor tree leaf could indicate N deposition in air. Conclusion] The monitoring of atmospheric environment by vascular plant was feasible.