生态学报2017，Vol.37Issue(7)：2334-2341,8.DOI:10.5846/stxb201511202348
北京地区典型落叶阔叶乔木叶片含氮量和δ15N值对大气氮沉降的响应
Responses and Indications of Foliar Nitrogen Contents and δ15N values to Atmospheric Nitrogen Deposition in Beijing, China
摘要
Abstract
With 60％ of the total area located in the North China Plain,Beijing suffered with very high atmospheric nitrogen (N) deposition in the south part,which was as high as 100 kg hm-2 a-1 including both organic and inorganic nitrogenous species from both wet and dry deposition.To test the responses of foliar N contents of plants,a collection of deciduous broadleaf tree leaves was conducted across Beijing areas.Typical deciduous broadleaf trees,Populus and Salix were selected at 189 sites,which were firstly designed at 5-decimal minute in latitude and longitude grid resolution and then excluded sites without Populus or Salix species.Leaf sampling collection was carried out in the end of August corresponding to annual peak-standing biomass in late summer.Five trees of every species at each site were selected,and five mature leaves of every tree were collected.All the leaf samples were over-dried at 105℃ for 10 minutes and then 65℃ for 48 hours to constant mass.Samples of each species at each site were put together and grounded with a mill to pass 1-mm sieve for N contents analysis.Foliar N was determined following Kjeldehl digestion and δ15N values were determined by continuous flow isotoperatio mass spectrometer.The foliar N contents were (24.0±4.0) g/kg and (25.9±4.1) g/kg on average for Populus and Salix,respectively.Spatial variations of both the two genus showed similar trends,with higher foliar N contents in the southeast and lower foliar N contents in the northwest,consisting with the spatial variation of atmospheric N deposition in Beijing area.The foliar δ15N values were (1.15±2.48)‰o and (2.31±2.60)‰o on average for Populus and Salix,respectively.However,the spatial variation trends of δ15N values were contrary with the foliar N contents.Higher δ15N values were found in the city center and northwest,while lower δ15N values were found in the southeast.With the different δ15N values of potential sources,the higher δ15N values in the city center indicated the traffic emission sources,the higher δ15N values in the northwest indicated the natural N cycling,while the lower δ15N values indicated both the agricultural and traffic pollution.关键词
落叶阔叶乔木/叶片含氮量/δ15N/大气氮沉降/北京地区Key words
Deciduous broadleaf trees/foliar N content/δ15N/atmospheric N deposition/Beijing area引用本文复制引用
刘超明,唐美庆,马坤,刘星韵,于涵,张颖..北京地区典型落叶阔叶乔木叶片含氮量和δ15N值对大气氮沉降的响应[J].生态学报,2017,37(7):2334-2341,8.基金项目
北京市优秀人才培养资助项目(2014000020124G073) （2014000020124G073）
国家自然科学基金资助项目(41503077) （41503077）
北京林业大学科技创新计划资助项目(BLX20120022) （BLX20120022）
