Chin J Plan Ecolo ›› 2017, Vol. 41 ›› Issue (1): 126-135.DOI: 10.17521/cjpe.2016.0031

Special Issue: 中国灌丛生态系统碳储量的研究专辑

• Research Articles • Previous Articles     Next Articles

Stoichiometric characteristics of carbon, nitrogen and phosphorus of Sibiraea angustata shrub on the eastern Qinghai-Xizang Plateau

He-Liang HE1,2, Xiao-Cheng YANG2, Dan-Dan LI1, Chun-Ying YIN1, Yun-Xiang LI3, Guo-Ying ZHOU4, Lin ZHANG5, Qing LIU1,*()   

  1. 1Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China;
    2 College of Material and Chemistry & Chemical Engineering, Chengdu University of Technology, Chengdu 610059, China;

    3The School of Life Science, China West Normal University, Nanchong, Sichuan 637009, China

    4Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China
    and
    5Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
  • Received:2016-01-17 Accepted:2016-09-21 Online:2017-01-10 Published:2017-01-23
  • Contact: Qing LIU
  • About author:

    KANG Jing-yao(1991-), E-mail: kangjingyao_nj@163.com

Abstract:

Aims Little is known about the stoichiometric characteristics of carbon (C), nitrogen (N) and phosphorus (P) in plateau shrubs across China. Sibiraea angustata is a typical and representative shrub species on the eastern Qinghai- Xizang Plateau, and exploring its C, N and P distribution patterns and stoichiometric properties in different organs (including root, shoot, leaf, twig and fruit) would help us better understand the mechanisms of C, N and P cycling and balance in the S. angustata dominated shrub ecosystem.
Methods Sixteen sampling sites were selected on the eastern Qinghai-Xizang Plateau by the stratified sampling method. The height and coverage of the dominant shrubs, latitude, longitude and altitude of the sites were recorded. Three 5 m × 5 m plots were selected at each site. At least 128 biological samples of plant organs of S. angustata were collected and measured, respectively. The C and N concentrations of plant samples were analyzed using an elemental analyzer (2400 II CHNS). The P concentration was analyzed using the molydate/ascorbic acid method after H2SO4-H2O2 digestion.
Important findings The C, N and P concentrations of different organs followed the order of: shoot (495.07 g·kg-1) > twig (483.37 g·kg-1) > fruit (480.35 g·kg-1) > root (468.47 g·kg-1) > leaf (466.33 g·kg-1); leaf (22.27 g·kg-1) > fruit (19.74 g·kg-1) > twig (7.98 g·kg-1) > shoot (4.54 g·kg-1) > root (4.00 g·kg-1) and fruit (2.85 g·kg-1) > leaf (1.92 g·kg-1) > twig (0.96 g·kg-1) > root (0.52 g·kg-1) > shoot (0.45 g·kg-1), respectively. The ranges of the coefficient of variation (CV) for C, N and P concentrations were 1.71%-4.44%, 14.49%-25.50% and 11.46%-46.15%, respectively. Specifically, the C concentration was relatively high and stable, and the maximum CV values for N and P were found in roots. The N:P value of different organs varied from 7.12-12.41 and the minimum CV for N:P was found in twig, which indicated that N:P in twig had higher internal stability. In addition, correlation analysis indicated that the C concentration was significantly negatively correlated with N and P concentrations and correlation coefficients were -0.407 and -0.342, respectively. However, N concentration had dramatically positive correlation with P concentration and the correlation coefficient was 0.814. These results also could indicate that the C, N and P stoichiometric characteristics in the S. angustata shrub accorded with the homeostatic mechanism and growth rate hypothesis to some extent, the distributions of C, N and P concentrations were closely related to the function of the organs and it should be prudent to use ecological stoichiometric ratios to judge the condition of nutrient limitation at the species level.

Key words: Sibiraea angustata, ecological stoichiometry, plant organs, Qinghai-Xizang Plateau