Chin J Plant Ecol ›› 2014, Vol. 38 ›› Issue (2): 116-124.DOI: 10.3724/SP.J.1258.2013.00038

Special Issue: 稳定同位素生态学 青藏高原植物生态学:群落生态学

• Research Articles • Previous Articles     Next Articles

Nitrogen uptake and allocation characteristics of alpine meadow main species under water and nitrogen additions based on 15N isotope

DENG Jian-Ming2*, YAO Bu-Qing1*, ZHOU Hua-Kun1,**(), ZHAO Xin-Quan1, WEI Qing3, CHEN Zhe1,4, WANG Wen-Ying3   

  1. 1Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810001, China
    2School of Life Science, Lanzhou University, Lanzhou 730000, China
    3Department of Life and Geography Sciences, Qinghai Normal University, Xining 81008, China
    4University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2013-01-04 Accepted:2013-04-07 Online:2014-01-04 Published:2014-02-12
  • Contact: ZHOU Hua-Kun


Aims Resource-use differentiation among species, which can reduce species competition for the same resources, is the main mechanism to maintain species diversity. Changes in soil temperature and moisture conditions, in the context of global change, may affect nitrogen (N) nutrition of plants of alpine meadow ecosystems. Our objective is to compare the characteristics of N uptake and resource allocation of dominant species of alpine meadow with changes in soil N and water.
Methods An alpine meadow was treated with N and water addition for three years using the method of 15N isotope injection. We determined the growth responses of dominant species to the N and water additions, as well as the features of N uptake capacity, N allocation and root to shoot ratio.
Important findings The species showed significantly different responses to the N and water treatments, with respect to functional traits of species in N absorption capacity, root N content and root to shoot ratio. There was no significant relationship between N absorption capacity and root N content, whereas N absorption capacity was negatively correlated with root to shoot ratio across all plant species. These results indicated there was ecological niche differentiation in N uptake and a trade-off between the N absorption capacity and resource allocation strategies among species.

Key words: 15N label, alpine meadow, N-absorption, niche differentiation, nitrogen addition, water addition