Nitrogen isotope variations in camphor (Cinnamomum Camphora) leaves of different ages in upper and lower canopies as an indicator of atmospheric nitrogen sources.
Nitrogen isotopic composition of new, middle-aged and old camphor leaves in upper and lower canopies has been determined in a living area, near a motorway and near an industrial area (Jiangan Chemical Fertilizer Plant). We found that at sites near roads, more positive δ(15)N values were observed in the camphor leaves, especially in old leaves of upper canopies, and ∆δ(15)N=δ(15)N(upper)-δ(15)N(lower)>0, while those near the industrial area had more negative δ(15)N values and ∆δ(15)N<0. These could be explained by two isotopically different atmospheric N sources: greater uptake from isotopically heavy pools of atmospheric NO(x) by old leaves in upper canopies at sites adjacent to roads, and greater uptake of (15)N-depleted NH(y) in atmospheric deposition by leaves at sites near the industrial area. This study presents novel evidence that (15)N natural abundance of camphor leaves can be used as a robust indicator of atmospheric N sources.
State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, No. 46, Guanshui Road, Guiyang 550002, China. xiaohuayun@vip.skleg.cn
Hua-Yun
HY
Xiao
Liang-Hong
LH
Wu
Ren-Guo
RG
Zhu
Yan-Li
YL
Wang
Cong-Qiang
CQ
Liu
D000388:Air / Q000032:analysis*; D027423:Cinnamomum camphora / Q000737:chemistry* / Q000254:growth & development; D004784:Environmental Monitoring / Q000379:methods*; D009587:Nitrogen Isotopes / Q000032:analysis*; D018515:Plant Leaves / Q000737:chemistry / Q000254:growth & development
D009587:Nitrogen Isotopes