植物生态学报 ›› 2006, Vol. 30 ›› Issue (1): 57-63.DOI: 10.17521/cjpe.2006.0008

所属专题: 稳定同位素生态学

• 研究论文 • 上一篇    下一篇

三峡库区岸边共存松栎树种水分利用策略比较

孙双峰1,2, 黄建辉1,*(), 林光辉1, 韩兴国1   

  1. 1 中国科学院植被数量生态学重点实验室,北京 100093
    2 中国科学院研究生院,北京 100039
  • 收稿日期:2005-03-28 接受日期:2005-09-29 出版日期:2006-03-28 发布日期:2006-01-30
  • 通讯作者: 黄建辉
  • 作者简介:*E-mail:jhhuang@ibcas.ac.cn
  • 基金资助:
    中国科学院知识创新工程方向资助项目(KSCX2-SW-109);中国科学院“百人计划”资助项目

CONTRASTING WATER USE STRATEGY OF CO-OCCURRING PINUS-QUERCUS TREES IN THREE GORGES RESERVOIR

SUN Shuang-Feng1,2, HUANG Jian-Hui1,*(), LIN Guang-Hui1, HAN Xing-Guo1   

  1. 1 Laboratory of Quantitative Vegetation Ecology, Chinese Academy of Sciences, Beijing 100093, China
    2 Graduate School of Chinese Academy of Sciences, Beijing 100039, China
  • Received:2005-03-28 Accepted:2005-09-29 Online:2006-03-28 Published:2006-01-30
  • Contact: HUANG Jian-Hui

摘要:

对三峡库区木鱼岛上马尾松(Pinus massoniana)、槲栎(Quercus aliena)和栓皮栎(Q. variabilis)组成的针阔混交林成林和幼林的光合速率(Pn)、气孔导度(Gs)、清晨和中午水势(ψpdψmd)以及叶片稳定碳同位素(δ13C)进行了测定。实验结果表明:针叶树马尾松PnGs均低于阔叶树槲栎和栓皮栎(差异达到极显著水平,p<0.001),但马尾松内在水分利用效率(WUEi, Pn/Gs)却高于槲栎(p=0.003)和栓皮栎(p=0.025)。反映了裸子植物和被子植物木质部不同的水力特性。针阔叶树幼树的PnGs高于成年树,但WUEiδ13C却低于成年树。表明水分利用效率与水分在树体内传输的距离有关。幼树属于挥霍型水分利用策略,成年树属保守型水分利用策略。三峡大坝的建设所造成的生态环境的改变可能会对三峡库区针阔混交林的演替产生一定的影响,但这需要长期的研究。

关键词: 三峡, 松栎混交林, 水分利用效率, 水势, 稳定碳同位素

Abstract:

With the rise of water level, the construction of the Three-Gorges Dam may have significant impacts on plant carbon-water relation and ecosystem properties in this region. To understand how the plants in this region adapt to the changes in water environments, we measured gas exchange, water potential and δ 13C of sapling and mature trees of three co-occurring coniferous and deciduous species: Pinus massoniana, Quercus variabilis and Q. aliena, all are dominant tree species in this region. The two deciduous broad-leaf trees (Q. variabilis and Q. aliena) exhibited higher photosynthetic (Pn) and stomatal conductance (Gs) than the evergreen conifer species (P. massoniana). The predawn water potential (ψpd) of P. massoniana was lower than that of the two broad-leaf species. Intrinsic water use efficiency (WUEi, Pn/Gs) of P. massoniana was higher than those of Q. variabilis and Q. aliena. However, the differences in carbon isotope ratio (δ13C) of leaves among species, which gives integrative information of WUE in growing season period, were not statistically significant. We also compared eco-physiological parameters between saplings and mature trees of these three species. The Pn and Gs values of the mature trees were significantly lower than those of the saplings. The mature trees showed lower ψpd value, but the difference between the mature trees and the saplings was not statistically significant. However, the WUEi values of all mature trees were significantly higher than those of the saplings. The δ13C values of mature trees showed more positive than those of corresponding saplings, indicating also higher WUE in the mature trees. From these results, we concluded that 1) P. massoniana showed different water use strategies from two Quercus trees species, and 2) the mature trees of these three dominant tree species showed lower photosynthetic rate but higher WUE than those of their corresponding saplings.

Key words: Three Gorges, Pinus-Quercus community, Water use efficiency, Water potential, Carbon isotope ratio