植物生态学报 ›› 2015, Vol. 39 ›› Issue (8): 816-824.DOI: 10.17521/cjpe.2015.0078

所属专题: 青藏高原植物生态学:种群生态学

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高寒草地甘肃臭草根系分形结构的坡向差异性

宋清华, 赵成章*(), 史元春, 杜晶, 王继伟, 陈静   

  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:2015-02-03 接受日期:2015-05-20 出版日期:2015-08-01 发布日期:2015-08-17
  • 通讯作者: 赵成章
  • 作者简介:

    *作者简介:E-mail:dengchuanyuan@163.com

  • 基金资助:
    国家自然科学基金(41461013和91125- 014)和甘肃省生态学重点学科

Fractal root system of Melica przewalskyi along different aspect in degraded grassland

SONG Qing-Hua, ZHAO Cheng-Zhang*(), SHI Yuan-Chun, DU Jing, WANG Ji-Wei, CHEN Jing   

  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:2015-02-03 Accepted:2015-05-20 Online:2015-08-01 Published:2015-08-17
  • Contact: Cheng-Zhang ZHAO
  • About author:

    # Co-first authors

摘要:

根系分形结构是植物根系构型应对环境异质性的表型可塑性结果, 可反映植物对生长环境的适应策略。利用ArcGIS建立研究区域的数字高程模型, 并提取坡向数据, 采用全根挖掘和Win-RHIZO根系分析仪相结合的方法, 研究了祁连山北坡高寒退化草地不同坡向甘肃臭草(Melica przewalskyi)的根系分形结构。结果表明: 随着坡向由北坡向东坡、西坡、南坡转变, 草地群落的密度、高度和土壤含水量逐渐减小, 甘肃臭草种群的密度、高度以及根系分形丰度呈逐渐增大的趋势、分形维数逐渐减小; 不同坡向甘肃臭草根系分形维数和分形丰度间的相关性存在差异(p < 0.05), 南坡和北坡甘肃臭草根系分形维数分形丰度之间存在极显著负相关关系(p < 0.01), 东坡和西坡之间存在显著负相关关系(p < 0.05), 甘肃臭草根系分形维数和分形丰度存在着“此消彼长”的权衡关系; 随着坡向由北坡向东坡、西坡、南坡转变, 甘肃臭草根系分形维数和分形丰度回归方程的标准化主轴(SMA)斜率逐渐增大(p < 0.05), 说明在干旱的南坡, 根系所开发利用的相同体积的土壤内, 根系分支更少、更稀疏。不同坡向甘肃臭草合理权衡根系分形维数和分形丰度的资源配置模式, 体现了植物根系构型构建的资源投资权衡机制。

关键词: 坡向, 根系构型, 甘肃臭草, 分形结构, 分形维数, 分形丰度

Abstract:

Aims Fractal root system is phenotypic plasticity result of plant root architecture to respond to environmental heterogeneity, may reflect the growth strategy of plants to adapt to environmental conditions. Our objective was to explore the relationship between root fractal dimension and fractal abundance of fractal root system of Melica przewalskyi population in response to aspect variation in the northwest of China. Methods The study site was located in a degraded alpine grassland on the northern slope in Qilian Mountains, Gansu Province, China. Survey and sampling were carried out at 40 plots which were set up along four slope aspects transects with 20 m distance between adjacent plots. Handheld GPS was used to determine the elevation, longitude and latitude of each plot. ArcGIS was used to set up digital elevation model (DEM). Community traits were investigated and six individuals roots of M. przewalskyi were collected randomly at each plot. The samples were cleaned and divided into different organs, then scanning the root with the Win-RHIZO for measurements of fractal dimension and fractal abundance in laboratory, and their biomass were then measured after being dried at 80 °C in an oven. Important findings With the slope aspect turned from north to east, west, and south, the density, height and soil moisture content of the plant community displayed a pattern of initial decline, the height, density, root fractal abundance of M. przewalskyi increased and the root fractal dimension decreased. The root fractal dimension was negatively associated with the fractal abundance in all aspects, but the relationship varied along the slope aspects gradient; there was a highly significant negative correlation (p < 0.01) between the root fractal dimension and fractal abundance at north slope and south slope aspect, whereas the correlation only reached a significant level (p < 0.05) at the east slope aspect and west slope aspect; indicating that there is a trade-off between the root fractal dimension and fractal abundance. In addition, when the slope aspect changed from north to east, west and south, the standardized major axis (SMA) slope of the regression equation in the scaling relationships between root fractal dimension and fractal abundance increased (p < 0.05), indicating that the roots of M. przewalskyi at the droughty southern slope have less branch and more sparse in the same soil volume of root exploitation and utilization. Consequently, the resource allocation pattern on reasonable trade-off between root fractal dimension and fractal abundance in different slope aspect of M. przewalskyi, reflects the relationship between the income and the cost of construction of plant root architecture.

Key words: aspect, root architecture, Melica przewalskyi, fractal root system, fractal dimension, fractal abundance