科研之友
微信
新浪微博
Facebook
分享链接
摘要
Atmospheric nitrogen deposition affects nitrogen isotope composition (delta N-15) in plants. However, both negative effect and positive effect have been reported. The effects of climate on plant delta N-15 have not been corrected for in previous studies, this has impeded discovery of a true effect of atmospheric N deposition on plant delta N-15. To obtain a more reliable result, it is necessary to correct for the effects of climatic factors. Here, we measured delta N-15 and N contents of plants and soils in Baiwangshan and Mount Dongling, north China. Atmospheric N deposition in Baiwangshan was much higher than Mount Dongling. Generally, however, foliar N contents showed no difference between the two regions and foliar delta N-15 was significantly lower in Baiwangshan than Mount Dongling. The corrected foliar delta N-15 after accounting for a predicted value assumed to vary with temperature was obviously more negative in Baiwangshan than Mount Dongling. Thus, this suggested the necessity of temperature correction in revealing the effect of N deposition on foliar delta N-15. Temperature, soil N sources and mycorrhizal fungi could not explain the difference in foliar delta N-15 between the two regions, this indicated that atmospheric N deposition had a negative effect on plant delta N-15. Additionally, this study also showed that the corrected foliar delta N-15 of bulk data set increased with altitude above 1300 m in Mount Dongling, this provided an another evidence for the conclusion that atmospheric N deposition could cause N-15-depletion in plants.
