植物生态学报 ›› 2010, Vol. 34 ›› Issue (3): 279-288.DOI: 10.3773/j.issn.1005-264x.2010.03.005

• 研究论文 • 上一篇    下一篇

不同氮素水平下增温及[CO2]升高综合作用对蒙古栎幼苗生物量及其分配的影响

马立祥, 赵甍, 毛子军*(), 刘林馨, 赵溪竹   

  1. 东北林业大学森林植物生态学教育部重点实验室, 哈尔滨 150040
  • 收稿日期:2009-02-16 接受日期:2009-06-20 出版日期:2010-02-16 发布日期:2010-03-01
  • 通讯作者: 毛子军
  • 作者简介:* E-mail: zijunm@yahoo.com.cn

Effects of elevated temperature and [CO2] under different nitrogen regimes on biomass and its allocation in Quercus mongolica seedlings

MA Li-Xiang, ZHAO Meng, MAO Zi-Jun*(), LIU Lin-Xin, ZHAO Xi-Zhu   

  1. Key Laboratory of Forest Plant Ecology of Ministry of Education, Northeast Forestry University, Harbin 150040, China
  • Received:2009-02-16 Accepted:2009-06-20 Online:2010-02-16 Published:2010-03-01
  • Contact: MAO Zi-Jun

摘要:

蒙古栎(Quercus mongolica)是东北地区天然次生林重要组成树种, 研究该树种对未来气候变暖的响应, 可为预测未来气候变暖情况下蒙古栎林的发展动态、制定合理的经营措施提供科学参考。该文旨在探讨不同的供氮水平下, CO2浓度和温度升高综合作用对蒙古栎幼苗生物量及其分配的影响。实验采用人工气候箱控制, 控制条件分别为温度升高4 ℃(ET)、CO2浓度倍增(700 μmol CO2 ·mol-1) × 温度升高4 ℃ (ECET)和对照(正常温度, CO2浓度为400 μmol CO2·mol-1) (CK), 每个控制条件幼苗的基质分别用3种氮素水平处理: N1 (15 mmol·L-1 N)、N2 (7.5 mmol·L-1 N)和N3 (不施氮)。研究结果显示, 1)在ET条件下, N1明显促进幼苗茎的高生长、径生长和生物量积累, 幼苗生物量的分配随氮素浓度的增加, 地下生物量所占的比例增大。2) ECET条件下N1明显促进幼苗的高生长, 但对径生长影响不显著, 对幼苗总生物量积累的影响不显著。但N1增加了地下生物量的比例。3) ET与ECET条件下幼苗叶片的碳氮比均随供氮水平降低而升高, 但ECET下碳氮比的升高是由于叶片碳含量较高引起的, 而ET条件下则是由于叶片氮含量的降低而引起的。ECET和ET条件较低的氮素供应水平综合作用对蒙古栎幼苗的生物量积累无促进作用。因此, 在未来气候变化情况下, 土壤中充足的氮供给可能将促进蒙古栎幼苗的生长, 增加其天然更新潜力, 并增加其碳库容。

关键词: 生物量分配, CO2升高, 温度升高, 氮素, 蒙古栎

Abstract:

Aims The cold temperate zone is very sensitive to climate change. Forests in this region provide a natural laboratory for studying effects of climate warming on terrestrial ecosystems. Our objective was to study the biomass responses of seedlings of a main secondary forest species, Quercus mongolica, to experimental warming and the interaction of elevated CO2 and different nitrogen regimes to provide insights into community development under a future warmer climate.

Methods We used large growth chambers to determine short-term effects of elevated temperature (+ 4 °C) (ET) only and the combination of elevated CO2 concentration (700 μmol CO2·mol-1) and elevated temperature (+ 4 °C) (ECET) under three different nitrogen regimes (15 mmol·L-1 N (N1), 7.5 mmol·L-1 N (N2) and no added N in soil substrate (N3)) on growth, biomass and its allocation in Q. mongolica seedlings.

Important findings The ET and N1 combination generally increased growth in height and diameter, as well as biomass accumulation of the seedlings. The allocation of underground biomass of seedlings increased with the increasing of N concentration. The ETEC and N1 combination increased growth in height and underground biomass allocation of the seedlings, but there was no significant effect on diameter growth and total biomass of the seedlings. The C/N ratio of leaves increased with decreasing nitrogen supply, but the increases of C/N ratio under ECET was due to decreasing nitrogen concentration in the leaves and under ET was due to increasing carbon concentration in the leaves. No promotion of biomass accumulation was found under ECET and ET with lower nitrogen supply. So nitrogen supply will be an important factor with future climate change. Sufficient nitrogen supply may promote the growth of Q. mongolica seedlings, lead to changes in regeneration dynamics and increase their carbon stock under the future climate.

Key words: biomass allocation, elevated CO2, elevated temperature, nitrogen, Quercus mongolica