Chin J Plan Ecolo ›› 2015, Vol. 39 ›› Issue (11): 1062-1070.DOI: 10.17521/cjpe.2015.0103

• Orginal Article • Previous Articles     Next Articles

Trade-off relationship between root forks and branch angle of Reaumuria songarica on different aspects of slopes

ZHENG Hui-Ling, ZHAO Cheng-Zhang*(), XU Ting, DUAN Bei-Bei, HAN Ling, FENG Wei   

  1. College of Geography and Environmental Science, Northwest Normal University, Research Center of Wetland Resources Protection and Industrial Development Engineering of Gansu Province, Lanzhou 730070, China
  • Received:2015-06-21 Accepted:2015-09-20 Online:2015-11-01 Published:2015-12-02
  • Contact: Cheng-Zhang ZHAO
  • About author:

    # Co-first authors


Aims Root architecture is a major determinant in root spatial distribution and soil searching efficiency, may reflect plant strategies to adapt to the environments. Our objective was to examine the relationship between root forks and branch angle of Reaumuria songarica in response to slope aspects in the northwest of China.Methods The study site was located in desert grasslands on the northern slope of Qilian Mountains, Gansu Province, China. Survey and sampling were carried out along 20 belt transects. It were set up on sites of four different slope aspects at intervals of 30 m vertically from elevation 1940 m of the study area moving upward, 6 plots were set up flatly on site of each belt transect at intervals of 20 m. A handheld GPS was used to record longitude, latitude and altitude of each plot. ArcGIS was used to set up digital elevation model to extract the information of elevation, aspect, and slope for each plot. The traits of plant communities were investigated and 1 individual’s samplings of R. songarica were used to measure the root forks, root length and root branch angle in laboratory in each plot, and biomass of different organs was measured after being dried at 80 °C in an oven. The 120 plots were categorized into groups of south, west, east, and north aspects of slopes, and the linear regression analysis was then used to examine the trade-off relationship between root forks and branch angle in various groups.Important findings The results showed that with the slope aspect turned from south, west, east to north, the density, cover, height, above biomass and soil moisture content of the plant community displayed a pattern of initial increase, while the height, root-shoot ratio, root branch angle of R. songarica displayed a pattern of initial decrease, and the density, specific root length, root forks increase. The number of root forks was negatively associated with the branch angle, but the relationship varied along the aspect gradient (p < 0.05). There was a highly significant negative correlation (p < 0.01) between the root forks and branch angle on north slope and south slope, whereas less significant (p < 0.05) on the east slope and west slope. There is a trade-off relationship between the root forks and link length. In addition, when the slope aspect changed from south to west, east and north, the standardized major axis slope of regression equation in the scaling relationships between root forks and branch angle decrease (p < 0.05), indicating that the root architecture model of R. songarica by diffusion to gather. Consequently, the patterns of resource allocation between root forks and branch angle in different slope habitats reflected the mechanism of environment adaptation under conditions of multiple competitions for resources in plant populations.

Key words: Reaumuria songarica, root architecture, root forks, root branch angle, aspect