Chin J Plant Ecol ›› 2009, Vol. 33 ›› Issue (1): 118-124.DOI: 10.3773/j.issn.1005-264x.2009.01.013

• Research Articles • Previous Articles     Next Articles

VARIATIONS OF NONSTRUCTURAL CARBOHYDRATE CONTENT IN BETULA ERMANII AT DIFFERENT ELEVATIONS OF CHANGBAI MOUNTAIN, CHINA

ZHOU Yong-Bin1(), WU Dong-Dong1, YU Da-Pao2, SUI Chen-Ying1   

  1. 1College of Forestry, Shenyang Agricultural University, Shenyang 110161, China
    2Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
  • Received:2008-04-28 Accepted:2008-06-05 Online:2008-04-28 Published:2009-01-30

Abstract:

Aims It is often assumed that trees near the high-elevation tree limit fall short in photosynthate (source limitation). Alternatively, low temperature may restrict carbon investment (growth, sink limitation). The content of mobile nonstructural carbohydrates (NSC) in tissues is considered as a measure of the carbon source-sink balance. Our objective was to test source vs. sink limitation. We compared late-season NSC concentrations in leaves and branches of Betula ermanii across elevational gradients from the subalpine forest interior to tree line on the north slope of Changbai Mountain, China.
Methods We sampling the leaves and branches of B. ermanii on August 25, 2007. The NSC (including dissolubility total sugar, sucrose, and fructose) concentration was measured using a modified anthrone method; the perchloric acid method was used for starch concentration measure.
Important findings The NSC (including starch) concentrations in branches increased significantly with elevation, while there were no significant trend in leaves. The ratio of starch to sugar decreased with elevation in branches and leaves. The overall elevational trends of the NSC revealed no depletion of carbon reserves near the tree limit, suggesting that sink limitation predominates across this treeline ecotone community.

Key words: Betula ermanii, nonstructural carbohydrates, elevation, timberline, Changbai Mountain