植物生态学报 ›› 2010, Vol. 34 ›› Issue (1): 48-57.DOI: 10.3773/j.issn.1005-264x.2010.01.008

所属专题: 生态化学计量

• 生态化学计量学专题论文 • 上一篇    下一篇

浙江天童常绿阔叶林、常绿针叶林与落叶阔叶林的C:N:P化学计量特征

阎恩荣1,2,*(), 王希华1,2, 郭明1,2, 仲强1,2, 周武1,2   

  1. 1华东师范大学环境科学系, 上海 200062
    2浙江天童森林生态系统国家野外科学观测研究站, 浙江宁波 315114
  • 收稿日期:2008-06-17 接受日期:2009-01-04 出版日期:2010-06-17 发布日期:2010-01-01
  • 通讯作者: 阎恩荣
  • 作者简介:* E-mail: eryan@des.ecnu.edu.cn

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

摘要:

以浙江天童常绿阔叶林、常绿针叶林和落叶阔叶林为对象, 通过对叶片和凋落物C:N:P比率与N、P重吸收的研究, 揭示3种植被类型N、P养分限制和N、P重吸收的内在联系。结果显示: 1)叶片C:N:P在常绿阔叶林为758:18:1, 在常绿针叶林为678:14:1, 在落叶阔叶林为338:11:1; 凋落物C:N:P在常绿阔叶林为777:13:1, 常绿针叶林为691:14:1, 落叶阔叶林为567:14:1; 2)常绿阔叶林和常绿针叶林叶片与凋落物C:N均显著高于落叶阔叶林; 叶片C:P在常绿阔叶林最高, 常绿针叶林中等, 落叶阔叶林最低, 常绿阔叶林和常绿针叶林凋落物C:P显著高于落叶阔叶林; 叶片N:P比也是常绿阔叶林最高、常绿针叶林次之, 落叶阔叶林最低, 但常绿阔叶林凋落物N:P最低; 3)植被叶片N、P含量间(N为x, P为y)的II类线性回归斜率显著大于1 (p < 0.05), 表明叶片P含量的增加可显著提高叶片N含量; 凋落物N、P含量的回归斜率约等于1, 反映了凋落物中单位P含量与单位N含量间的等速损耗关系; 4)常绿阔叶林N重吸收率显著高于常绿针叶林与落叶阔叶林, 落叶阔叶林P重吸收率显著高于常绿阔叶林和常绿针叶林。虽然植被的N:P指示常绿阔叶林受P限制, 落叶阔叶林受N限制, 常绿针叶林受N、P的共同限制, 但是N、P重吸收研究结果表明: 受N素限制的常绿阔叶林具有高的N重吸收率, 受P限制的落叶阔叶林并不具有高的P重吸收率。可见, 较高的N、P养分转移率可能不是植物对N、P养分胁迫的一种重要适应机制, 是物种固有的特征。

关键词: C:N:P比率, II类线性回归, 养分限制, 养分重吸收, 化学计量学

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