|
Group-consistent but species-specific nitrogen isotope fractionation between leaves and roots in tropical vascular epiphytes
| First Author: |
Zhou, Chun-Yan |
| Abstract: |
1. Epiphytes are believed to exhibit minimal internal nitrogen (N) isotopic composition (delta N-15) variation due to severe N limitation in canopy habitats. However, the lack of empirical evidence leaves this question open, complicating the interpretation of foliar delta N-15 in understanding the N economy of epiphytes. 2. Here, the variation in delta N-15 between leaves and roots (triangle N-15(leaf-root)) of 24 epiphyte species from the tropical Xishuangbanna region of southwest China was calculated. Subsequent linear regression and variance decomposition were performed to identify the underlying driving factors. 3. A small triangle N-15(leaf-root) (+0.43 parts per thousand) was observed in epiphytes, which exhibited relatively consistent values across groups (-0.20 parts per thousand to 1.78 parts per thousand) but markedly species-specific values (-2.13 parts per thousand to 2.15 parts per thousand), independently of phylogeny, reflecting the combined effects of external N sources and N acquisition strategies of epiphytes. In particular, positive triangle N-15(leaf-root) values were primarily correlated with leaf N and root carbon (C), while negative triangle N-15(leaf-root) values were associated with leaf C isotopic composition (delta C-13), indicating that distinct N-15 fractionation progresses were at work. 4. Synthesis. These results demonstrate for the first time that triangle N-15(leaf-root) is minimal yet noteworthy within epiphytes compared with soil-rooted plants, reflecting the more severe N stress in the canopy habitats, and suggest that foliar delta N-15-when accounting for N-15 fractionation-can provide valuable insights into the N dynamics of tropical epiphytes. |
| Contact the author: |
Li, S;Na, XF |
| Page Number: |
|
| Issue: |
10 |
| Subject: |
|
| Impact Factor: |
5.6 |
| Authors units: |
|
| PubYear: |
2025 |
| Volume: |
113 |
| Publication Name: |
JOURNAL OF ECOLOGY |
| The full text link: |
|
| ISSN: |
|
| Download: |
Download Address |
|
|
|
|
