植物生态学报 ›› 2012, Vol. 36 ›› Issue (8): 819-830.DOI: 10.3724/SP.J.1258.2012.00819

• 研究论文 • 上一篇    下一篇

模拟增温和降水变化对北京东灵山辽东栎种子出苗和幼苗生长的影响

董丽佳1,2, 桑卫国1,*()   

  1. 1中国科学院植物研究所植被与环境变化国家重点实验室, 北京 100093
    2中国科学院研究生院, 北京 100049
  • 收稿日期:2011-12-12 接受日期:2012-05-16 出版日期:2012-12-12 发布日期:2012-08-21
  • 通讯作者: 桑卫国
  • 作者简介:* (E-mail: swg@ibcas.ac.cn)

Effects of simulated warming and precipitation change on seedling emergence and growth of Quercus mongolica in Dongling Mountain, Beijing, China

DONG Li-Jia1,2, SANG Wei-Guo1,*()   

  1. 1State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
    2Graduate University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2011-12-12 Accepted:2012-05-16 Online:2012-12-12 Published:2012-08-21
  • Contact: SANG Wei-Guo

摘要:

气候变化将增加地表平均气温、改变降水格局, 会影响到种子出苗和幼苗生长, 进而影响物种的更新动态。为探讨增温和降水变化对东灵山地区建群树种辽东栎(Quercus mongolica)种子出苗和一年生幼苗生长和适应状况的影响, 该文利用环境控制生长箱开展了温度和降水量的双因素控制实验, 温度设置3个梯度: 月平均气温(对照)、增温2 ℃和增温6 ℃; 降水量设置3个梯度: 月平均降水量(对照)、减水30%和加水30%。结果表明: 1)辽东栎的种子出苗率和一年生幼苗的生长对增温和降水变化的响应不一致, 种子出苗率主要受到降水及其与温度交互作用的影响, 幼苗生长仅受到温度和降水独立作用的影响; 2)春季增温2 ℃或降水量增加均使辽东栎种子出苗期提前; 增温6 ℃与降水量减少的水热组合延迟了种子出苗期并使其存活率和出苗率显著降低, 但在此温度下增加降水量则增加了出苗速率和出苗率。3)增温2 ℃对其生长无显著影响, 增温6 ℃则在不同水分条件下显著地增加了幼苗的比叶面积、抑制了叶的伸长生长, 同时也显著降低了各器官生物量积累, 并减少了幼苗生物量向根的分配; 降水量减少降低了幼苗根生物量, 但未影响总生物量和根冠比, 降水量增加显著促进了幼苗地上部分的生长, 特别是叶的生长。因此, 适当地增温或增加降水量将增加辽东栎幼苗的更新潜力, 但增温和降水量减少导致的干旱化将显著降低幼苗的更新潜力。

null

关键词: 气候变化, 东灵山, 更新, 幼苗, 种子

Abstract:

Aims Temperature and water supply are crucial drivers for plant seedling regeneration. Dongling Mountain is one of the temperate areas most sensitive to climate change in China, and Quercus mongolica is the dominant species. Our objective was to investigate how climate change (warming and precipitation change) affects the physiological and ecological processes of seeds and seedlings of Q. mongolica to determine the regeneration mechanisms and change in patterns of this key species.
Methods We used a controlled, growth-chamber experiment for rising temperature and changing water supply. There were three levels for both temperature and water supply: monthly mean temperature (control) over past the 18 years and increased by 2 °C and 6 °C and monthly mean precipitation (control) and +30% and -30%. Seeds of Q. mongolica were collected in fall of 2010, planted in May 2011, and grown in pots under the treatments. We periodically measured traits of seedling emergence and growth during the first growing season.
Important findings Seedling emergence percentage was affected by precipitation and its interaction with temperature, while seedling growth and biomass were affected by temperature and precipitation alone, rather than by their interaction. Increased temperature by 2 °C and water addition shortened the seedling emergence time; increased temperature by 6 °C combined with reduction of water increased seed mortality and reduced seedling emergence percentage, yet with water addition promoted seedling dynamics. Increased temperature by 2 °C had no significant effects on seedling growth, while increased by 6 °C significantly increased the specific leaf area, restricted the seedling growth and biomass, and reduced the ratio of root and shoot. In addition, water reduction reduced only root biomass but not shoot, total biomass and root:shoot. Water addition significantly promoted growth of leaf length, increased leaf numbers and increased aboveground biomass, especially leaf biomass. Therefore, proper temperature elevation or water addition may benefit the potential regeneration ability of Q. mongolica, but highly elevated temperature with reduced precipitation may be deleterious under future climate change.

Key words: climate change, Dongling Mountain, regeneration, seedling, seed