Chin J Plant Ecol ›› 2010, Vol. 34 ›› Issue (2): 125-133.DOI: 10.3773/j.issn.1005-264x.2010.02.003

Special Issue: 稳定同位素生态学

• Special feature: Stable isotope ecology • Previous Articles     Next Articles

Responses of foliar δ13C in Sabina przewalskii and Picea crassifolia to altitude and its mechanism in the Qilian Mountains, China

ZHANG Peng1, WANG Gang2, ZHANG Tao1, CHEN Nian-Lai1,*()   

  1. 1College of Resources and Environmental Science, Gansu Agriculture University, Lanzhou 730070, China
    2College of Life Sciences, Lanzhou University, Lanzhou 730000, China
  • Received:2008-10-08 Accepted:2009-01-21 Online:2010-10-08 Published:2010-02-01
  • Contact: CHEN Nian-Lai

Abstract:

Aims Sabina przewalskii and Picea crassifolia, widely distributed in the Qilian Mountains, were employed to analyze the response of leaf δ13C of subalpine trees to altitude and its mechanism.

Methods Leaf samples were taken at 2 600-3 600 m elevation in October 2007. The δ13C was determined using an isotope mass spectrometer, carbon content was estimated with the potassium dichromate method and nitrogen content was measured with the micro-Kjeldahl method. Data were evaluated with one-way analysis of variance and correlation analysis using SPSS version 11.5.

Important findings Foliar δ13C in both species was positively related to elevation (p < 0.000 1) and annual mean precipitation, but negatively related to annual temperature (p < 0.000 1). The δ13C value of S. przewalskii increased as leaf and soil water content increased, while that of P. crassifolia was not significantly related to soil water content, leaf water content, leaf N content or C/N ratio. Altitude, which can lead to changes of hydrothermal conditions, is the main factor influencing carbon isotope fractionation in these subalpine trees; however, the combined effects of various factors on the mechanism of action maybe more complicated and need further study.

Key words: altitudinal response, fractionation mechanism, leaf δ13C, Picea crassifolia, Qilian Mountains, Sabina przewalskii