植物生态学报 ›› 2010, Vol. 34 ›› Issue (3): 263-270.DOI: 10.3773/j.issn.1005-264x.2010.03.003

所属专题: 青藏高原植物生态学:种群生态学

• 研究论文 • 上一篇    下一篇

青藏高原东缘林线交错带糙皮桦幼苗光合特性对模拟增温的短期响应

徐振锋1,2, 胡庭兴1,*(), 张力1, 张远彬2, 鲜骏仁1, 王开运3   

  1. 1四川农业大学林学院, 四川雅安 625014
    2中国科学院成都生物研究所, 成都 610041
    3华东师范大学上海市城市化生态过程和生态恢复重点实验室, 上海 200062
  • 收稿日期:2009-03-02 接受日期:2009-04-23 出版日期:2010-03-02 发布日期:2010-03-01
  • 通讯作者: 胡庭兴
  • 作者简介:* E-mail: hutx001@yahoo.com.cn

Short-term gas exchange responses of Betula utilis to simulated global warming in a timberline ecotone, eastern Tibetan Plateau, China

XU Zhen-Feng1,2, HU Ting-Xing1,*(), ZHANG Li1, ZHANG Yuan-Bin2, XIAN Jun-Ren1, WANG Kai-Yun3   

  1. 1Faculty of Forestry, Sichuan Agricultural University, Ya’an, Sichuan 625014, China
    2Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
    3Shanghai Key Laboratory of Urbanization and Ecological Restoration, East China Normal University, Shanghai 200062, China
  • Received:2009-03-02 Accepted:2009-04-23 Online:2010-03-02 Published:2010-03-01
  • Contact: HU Ting-Xing

摘要:

采用开顶式生长室(OTC)模拟增温对植被影响的研究方法, 研究了青藏高原东缘林线交错带糙皮桦(Betula utilis)光合特性对模拟增温的响应。结果表明: 与对照样地相比, OTC内日平均气温(1.2 m)在植物生长季中增加2.9 ℃, 5 cm土壤温度增加0.4 ℃。增温使糙皮桦幼苗叶片的净光合速率(Pn)、蒸腾速率(Tr)和气孔导度(Gs)分别增加17.4%、21.4%和33.9%, 但对糙皮桦幼苗叶片的水分利用率(WUE)却没有明显影响, 而对糙皮桦的叶氮浓度却表现为显著的负效应。同时, 增温能显著增加糙皮桦幼苗的最大同化速率(Pnmax) (+19.6%)、暗呼吸速率(Rd) (+14.3%)、表观量子效率(AQY) (+7.9%), 但对其光补偿点(LCP)和光饱和点(LSP)却没有明显的影响。此外, 增温使糙皮桦幼苗叶片的最大羧化速率(Vcmax)和电子传递速率(J)分别增加了12.3%和11.7%, 而磷酸丙糖利用率(TPU)和CO2补偿点(CCP)对增温却并不敏感。该研究表明, 模拟增温对林线糙皮桦光合生理总体上表现为正效应, 这有可能帮助该物种对未来气候变化更快更好地适应。

关键词: 糙皮桦, 林线交错带, 开顶式生长室, CO2响应曲线, 光响应曲线

Abstract:

Aims Betula utilis is an important plant in the timberline ecotone of subalpine regions, Western Sichuan China. Our objective is to determine how this species changes its photosynthetic parameters under warming conditions.

Methods We studied the responses of gas exchange to simulated global warming using the open-top chamber (OTC) method. During the 2007 growing season, microclimate data between the OTC and the control (CK) were taken at 15-min intervals with an automatic recording system. In mid-August, the gas exchange of B. utilis seedlings in the OTC and the CK was measured with the LI-6400 Portable Photosynthesis System and a 6-cm2 leaf chamber. Comparisons between the OTCs and the control plots were analyzed by the Wilcoxon’s signed ranks test.

Important findings Warming significantly increased instantaneous leaf net photosynthetic rate (Pn), conductance (Gs) and transpiration (Tr) by 17.4%, 21.4% and 33.9%, respectively, and reduced leaf N concentration by 12.4%. Warming also enhanced the maximum net photosynthetic rate (Pnmax) (+19.6%), dark respiration rate (Rd) (+14.3%) and apparent quantum yield (AQY) (+7.9%), but did not influence the light compensation point (LCP) or the light saturation point (LSP) of B. utilis seedlings. Moreover, warming markedly increased the maximum rate of RuBP carboxylation (Vcmax) and rate of photosynthetic election transport (J), but there were no clear differences between treatments for triose phosphate use (TPU) and compensation CO2 (CCP). Our results indicated that in situ experimental warming had positive effects on the gas exchange of B. utilis seedlings. These responses could be helpful for the timberline species to adapt to future global warming.

Key words: Betula utilis, ecotone in timberline, open-top chamber, Pn -Ci curve, Pn -PAR curve