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冰川冻土 ›› 2015, Vol. 37 ›› Issue (1): 80-86.doi: 10.7522/j.issn.1000-0240.2015.0008

• 冰冻圈与全球变化 • 上一篇    下一篇

青海柴达木盆地林线附近祁连圆柏叶片功能性状的变化特征

杨淑丽1,2, 高贤良1, 陈立同1, 张晓玮1   

  1. 1. 兰州大学 生命科学学院 草地农业生态系统国家重点实验室, 甘肃 兰州 730000;
    2. 甘肃政法学院 人文学院, 甘肃 兰州 730070
  • 收稿日期:2014-07-07 修回日期:2014-11-19 出版日期:2015-02-25 发布日期:2015-03-23
  • 通讯作者: 张晓玮,E-mail:zhangxw08@lzu.edu.cn. E-mail:zhangxw08@lzu.edu.cn
  • 作者简介:杨淑丽(1978-),女,山东嘉祥人,讲师,2012年在兰州大学获硕士学位,现主要从事寒旱区生态研究和英语教学工作.
  • 基金资助:

    国家科技支撑计划项目(2011BAC07B05); 国家自然科学基金项目(31170571; 31370603)资助

Variations in leaf functional traits of Sabina przewalskii near the alpine timberline in Qaidam Basin, Qinghai

YANG Shuli1,2, GAO Xianliang1, CHEN Litong1, ZHANG Xiaowei1   

  1. 1. State Key Laboratory of Grassland Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou 730000, China;
    2. School of Humanities, Gansu Political Science and Law Institute, Lanzhou 730070, China
  • Received:2014-07-07 Revised:2014-11-19 Online:2015-02-25 Published:2015-03-23

摘要:

林线作为高山系统中郁闭林与无林高山植被带间特殊的生态过渡带, 对全球气候变化极为敏感. 柴达木盆地林线附近的祁连圆柏作为青藏高原东北部高山生态系统中海拔分布最高的单一优势树种, 是研究林线植物响应气候变化的理想材料. 为明确祁连圆柏重要叶片功能性状对林线附近环境变化的响应模式, 分别测定了东、西两个坡向上林线附近(郁闭林、林线和树线)祁连圆柏的叶片干物质含量(LDMC)、单位面积的叶片重量(LMA)、叶片碳稳定同位素(δ13C)、叶片单位重量的碳氮含量(Cmass, Nmass)、碳氮比(C/N)、叶片自由水含量(FW)和叶片自由水与束缚水比(FW/BW). 结果显示:LMA、δ13C和Cmass在林线附近无显著变化, 但林线和树线的Nmass、FW及FW/BW显著高于郁闭林, 而LDMC和C/N则相反; 在不同坡向上, 西坡LMA显著高于东坡. 此外, FW与LDMC、Nmass显著正相关, 而FW与FW/BW、LMA与Cmass以及Nmass与C/N显著负相关. 以上结果表明, 祁连圆柏作为我国西北高山生态系统中耐旱、耐寒的树种在林线附近并未受到明显的水分胁迫, 其可能主要通过提高叶片自由水含量、光合能力、含氮渗透调节物含量等策略来适应林线附近的恶劣生境, 以保证自身的正常生长发育.

关键词: 祁连圆柏, 林线, 坡向, 碳稳定同位素, 比叶重

Abstract:

As the special ecotone from the closed forest line to the tree limit in alpine zone, timberline is highly vulnerable to climate change, and the trees near the timberline are very sensitive to environmental change. Sabina przewalskii is the dominant tree species in alpine ecosystems in the northeast Tibetan Plateau, mainly distributed at dry south-facing and infertile slopes. To test the response patterns of the leaf functional traits in Sabina przewalskii along the environmental gradient near the alpine timberline, the following items were measured:leaf dry matter content (LDMC), leaf mass per unit area (LMA), leaf stable carbon isotope composition (δ13C), leaf carbon content per unit mass (Cmass), leaf nitrogen content per unit mass (Nmass), leaf carbon-nitrogen ratio (C/N), leaf free water content (FW) and the ratio of leaf free water content and leaf bound water content (FW/BW) in Sabina przewalskii on the west-facing and east-facing slopes near timberline of the Qaidam Basin in the northeast Tibetan Plateau. It is found that Nmass, FW and FW/BW of Sabina przewalskii located in the sites of treeline and tree species line were higher than that in the sites of closed forest, while that of LDMC and C/N showed the opposite patterns, even LMA, δ13C and Cmass had no remarkable changes in near timberline of both west-facing and east-facing slopes. Meanwhile, LMA only changed significantly near timberline in west-facing slope. In addition, FW was positively related with LDMC and Nmass, and negatively related with FW/BW. Negative relationships between LMA and Cmass, Nmass and C/N were also found. Overall, these results indicated that Sabina przewalskii as a drought and cold tolerant native tree species in the alpine ecosystem mainly accommodates the harsh environment by the way of higher leaf free water content, photosynthetic capacity and some nitrogenous compounds.

Key words: Sabina przewalskii, timberline, slope aspect, stable carbon isotope, leaf mass per area

中图分类号: 

  • Q944.5