植物生态学报 ›› 2014, Vol. 38 ›› Issue (3): 281-288.DOI: 10.3724/SP.J.1258.2014.00025

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不同坡向高寒退化草地狼毒株高和枝条数的权衡关系

侯兆疆, 赵成章*(), 李钰, 张茜, 马小丽   

  1. 西北师范大学地理与环境科学学院甘肃省湿地资源保护与产业发展工程研究中心, 兰州 730070
  • 收稿日期:2013-10-15 接受日期:2013-12-09 出版日期:2014-10-15 发布日期:2014-02-27
  • 通讯作者: 赵成章
  • 作者简介:*E-mail: zhaocz@nwnu.edu.cn
  • 基金资助:
    国家自然科学基金(91125014);国家自然科学基金(40971039);甘肃省科技支撑计划(1011FKCA157);甘肃省生态学重点学科项目

Trade-off between height and branch numbers in Stellera chamaejasme on slopes of different aspects in a degraded alpine grassland

HOU Zhao-Jiang, ZHAO Cheng-Zhang*(), LI Yu, ZHANG Qian, MA Xiao-Li   

  1. Research Center of Wetland Resources Protection and Industrial Development Engineering of Gansu Province, College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730070, China
  • Received:2013-10-15 Accepted:2013-12-09 Online:2014-10-15 Published:2014-02-27
  • Contact: ZHAO Cheng-Zhang

摘要:

权衡关系是生活史对策理论的基础, 株高和枝条数的权衡关系对理解植物在不同生境下的表型可塑性有重要意义。该研究选择祁连山北坡高寒退化草地, 利用ArcGIS建立研究区域的数字高程模型(DEM), 并提取样地坡向数据, 采用广义相加模型(GAM)与偏相关分析相结合的方法, 分析了不同坡向影响下狼毒(Stellera chamaejasme)种群株高和枝条数的关系。结果表明: 随着坡向由北坡转向东坡、南坡、西坡, 草地群落地上生物量和盖度呈“减小—增大—减小”的变化趋势, 群落高度则先增大后减小; 坡向是影响狼毒株高和枝条数空间分异的主要地形因子; 随着坡向由北、东转向西、南, 狼毒种群株高呈下降趋势, 而枝条数呈上升趋势, 二者表现出此消彼长的权衡关系, 狼毒植株比叶面积先增大后减小。不同坡向狼毒株高和枝条数的权衡关系, 反映了异质生境中资源多重竞争下狼毒生物量分配机制和提高种群适应性的种群更新策略。

关键词: 坡向, 枝条数, 祁连山北坡, 株高, 狼毒, 权衡

Abstract:

Aims Trade-off is the basis of life history strategy theory. Elucidation of the trade-off between plant height and branch numbers is important for understanding the phenotypic plasticity of plants under different habitat conditions. Our objective was to examine how Stellara chamaejasme would adapt to changes in slope aspect through trade-off between height and branch numbers.
Methods In a degraded alpine grassland on the northern slope of the Qilian Mountains, Gansu Province, China, 80 plots were set up on sites of four different aspects at intervals of 10 m vertically from the foot of an isolated hill moving upward. Handheld GPS was used to record latitude, longitude and altitude of each plot. Community traits were investigated and five S. chamaejasme plants were harvested randomly on each plot for measuring the plant height, brunch numbers, leaf area, and above-ground biomass. ArcGIS was used to construct the digital elevation model (DEM) and to extract data on elevation, aspect, slope, slope of slope, and slope of aspect for the study sites. The 80 plots were categorized into groups of north, east, south, and east aspects. Generalized additive model (GAM) was used to select the most effective terrain factors, and partial correlation analysis method was used to examine the trade-off between plant height and brunch numbers on sites of different aspects.
Important findings With a change of the aspect from north to east, south and west, the above-ground biomass and cover of the grassland community displayed a pattern of decline―increase―decline; whereas the average height of the community displayed a pattern of increase―decline. Aspect was the predominant terrain factor affecting spatial variations of the height and branch numbers in S. chamaejasme. When the aspect changed from north and east to west and south, the average height of S. chamaejasme populations declined and the branch numbers increased, resulting in a trade-off in the form of an inversed relationship between the height and branch numbers; whilst the specific leaf area increased first and then decreased. The trade-off between height and branch numbers with changes in slope aspect of the habitat reflected the mechanism of biomass allocation under conditions of multiple competitions for resources in diverse habitats and the regeneration strategy for enhanced adaptation in S. chamaejasme populations.

Key words: aspect, branch number, northern slope of Qilian Mountains, plant height, Stellera chamaejasme, trade-off