Chin J Plant Ecol ›› 2010, Vol. 34 ›› Issue (1): 48-57.DOI: 10.3773/j.issn.1005-264x.2010.01.008

Special Issue: 生态化学计量

• Special feature: Ecological Stoichiometry • Previous Articles     Next Articles

C:N:P stoichiometry across evergreen broad-leaved forests, evergreen coniferous forests and deciduous broad-leaved forests in the Tiantong region, Zhejiang Province, eastern China

YAN En-Rong1,2,*(), WANG Xi-Hua1,2, GUO Ming1,2, ZHONG Qiang1,2, ZHOU Wu1,2   

  1. 1Department of Environment Science, East China Normal University, Shanghai 200062, China
    2Tiantong National Forest Ecosystem Observation and Research Station, Ningbo, Zhejiang 315114, China
  • Received:2008-06-17 Accepted:2009-01-04 Online:2010-06-17 Published:2010-01-01
  • Contact: YAN En-Rong

Abstract:

Aims Little is known about constrained ratios of carbon, nitrogen, and phosphorus (C:N:P) in terrestrial ecosystems. Our objective was to examine the C:N:P stoichiometry and its relationship with N and P resorption in evergreen broad-leaved forests (EBLF), evergreen coniferous forests (CF) and deciduous broad-leaved forests (DF) at the regional scale.

Methods The study was conducted in Tiantong National Forest Park (29°52′ N, 121°39′ E), Zhejiang Province, eastern China. To estimate foliar and litter C:N:P ratios and N and P resorption efficiencies, we quantified the C, N and P concentrations in leaf and litterfall in EBLF, CF and DF. We used type II regression slopes (reduced major axis, RMA) to determine whether C:N:P stoichiometry varied across gradients of forest production and nutrients.

Important findings The C:N:P ratios in EBLF, CF and DF were 758:18:1, 678:14:1 and 338:11:1 in fresh leaves and 777:13:1, 691:14:1 and 567:14:1 in litterfall, respectively. The foliar C:N ratio was highest in CF, intermediate in EBLF and lowest in DF, while the foliar C:P and N:P ratios were highest in EBLF, intermediate in CF and lowest in DF. In contrast, the litterfall C:N and C:P ratios were higher in EBLF than in CF and DF, and there were no significant differences of N:P ratio among forests. The type II regression slope for N vs. P in leaves of overall plants was statistically >1, suggesting an increasing investment of N with increasing of P in fresh leaves. In contrast, the slope for N vs. P in litterfall approximated 1. N resorption in EBLF was significantly higher than in CF and in DF, but the highest P resorption was observed in DF. Although foliar N:P ratios indicated that EBLF was P limited, DF was N limited and CF was both N and P limited, the nutrient resorption efficiency did not respond with relatively high N resorption in EBLF and high P resorption in DF. We concluded that the relative higher resorption of N and P before leaf abscission could be an inherent property of plants, but was not a mechanism thought to have evolved to conserve nutrients in environments with limited N or P supply.

Key words: C:N:P ratio, model Type II regression, nutrient limitation, nutrient resorption, stoichiometry