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应用15N示踪法研究两种杨树叶片对PM2.5中NH4+的吸收

石婕,刘庆倩,安海龙,曹学慧,刘超,尹伟伦,夏新莉,郭惠红**   

  1. (北京林业大学生物科学与技术学院, 北京 100083)
  • 出版日期:2014-06-10 发布日期:2014-06-10

Foliar uptake of NH4+ in PM2.5 in seedlings of two poplar species using the technique of 15N tracing.

SHI Jie, LIU Qing-qian, AN Hai-long, CAO Xue-hui, LIU Chao, YIN Wei-lun, XIA Xin-li, GUO Hui-hong**   

  1. (College of Biological Science and Technology, Beijing Forestry University, Beijing 100083, China)
  • Online:2014-06-10 Published:2014-06-10

摘要:

NH4+等水溶性无机离子是细颗粒物(PM2.5)中的主要组成部分。本实验以毛白杨(Populus tomentosa)和欧美杨(Populus deltoids×Populus nigra)苗木为试材,应用15N示踪法研究2种表面结构不同的叶片对NH4+的吸收以及叶片吸收氮素后的运转和分配。结果表明:2种杨树在吸收叶面的15NH4+时存在明显差异,最大吸收速率均发生在处理后6 h,但毛白杨的最大吸收速率约为欧美杨的3倍;2种杨树叶片15N含量均在处理后24 h时达到峰值,而毛白杨叶片的15N含量约为欧美杨的4倍;叶片施用15N标记的硫酸铵溶液还可以显著增加2种杨树叶片氮素水平,处理7 d后毛白杨和欧美杨叶片全氮含量分别达到对照的1.26和1.36倍;植株各器官的氮素分配率(Ndff)值显示,功能叶吸收的氮素向植株上部和下部均有运输,毛白杨主要积累于茎部,而黑杨则将氮素运输至根系;处理7 d后叶片标记溶液的施用在不同程度上增强了2种杨树叶片的净光合速率,但对叶片的气孔导度无明显影响。
 

关键词: Biomod2, 物种分布模型, 大熊猫, MaxEnt

Abstract: Watersoluble inorganic ions such as NH4+ are the major components of fine particles (PM2.5). The absorption, distribution and utilization of NH4+ on the leaf surface of Populus tomentosa and P. deltoids × P. nigra seedlings were studied by using the 15N trace technique. Our results showed that 15NH4+ was absorbed rapidly by P. tomentosa and P. deltoids × P. nigra leaves and the rates of absorption all peaked 6 hours after solution application. Significant differences were observed in the absorption rate between two poplar species, with the maximum absorption rate of P. tomentosa being 3 times that of P. deltoids × P. nigra. The content of 15N in leaves peaked at the same time (24 hours after treatment) in the two species, but the maximum amount of 15N of P. tomentosa was about 4 times that of P. deltoids × P. nigra. Foliar application of 15Nlabeled ammonium sulfate (15NH4SO4) solution led to a significant increase of total nitrogen level in the leaves of both poplars. The leaf total N contents of P. tomentosa and P. deltoids × P. nigra were 1.26 and 1.36 times that of control 7 days after treatment, respectively. The Ndff values of different organs showed that the 15N absorbed by functional leaves was transported to both the upper and lower parts of the plants, which was mainly stored in stems of P. tomentosa, but transported to roots of P. deltoids × P. nigra. Foliar application of 15NH4SO4 enhanced the net photosynthetic rate of both poplars to varied degrees 7 days after treatment, but no significant effect on stomatal conductance was observed.

Key words: MaxEnt, giant panda, species distribution model, Biomod2