Chin J Plant Ecol ›› 2012, Vol. 36 ›› Issue (10): 1015-1023.DOI: 10.3724/SP.J.1258.2012.01015

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Response of root systems to soil heterogeneity and interspecific competition in Alhagi sparsi- folia

LUO Wei-Cheng1,2,3, ZENG Fan-Jiang1,2,*(), LIU Bo1,2,3, ZHANG Li-Gang1,2,3, SONG Cong1,2,3, PENG Shou-Lan1,2,3, Stefan K. ARNDT4   

  1. 1Xinjiang Institute of Ecology and Geography, Chinese Academic of Sciences, ürümqi 830011, China;
    2Cele National Field Science Observation and Research Station of Desert Grassland Ecosystem, Cele, Xinjiang 848300 China
    3Graduate University of Chinese Academy of Sciences, Beijing 100049, China
    4Department of Forest and Ecosystem Science, University of Melbourne, Creswick, VIC 3363, Australia
  • Received:2012-04-09 Accepted:2012-06-06 Online:2012-04-09 Published:2012-09-26
  • Contact: ZENG Fan-Jiang

Abstract:

Aims The responses of plant roots to soil heterogeneity and the interactive effects among plant roots have been important research topics in recent years. Most studies have focused on annual plant species and conducted experiments in controlled greenhouse conditions. Few comprehensive studies have been carried out on the response of perennial plant roots to soil heterogeneity and competition. Our objective is to investigate the responses and adaptive strategies of root-system growth of the perennial plant Alhagi sparsifolia to nutrient heterogeneity and competition.
Methods We used sheep feces as nutrient patches to form soil heterogeneity and planted A. sparsifolia in glass pools. Seedlings received one of six factorial combinations of soil heterogeneity (uniform, patch-center and patch-edge) and competition treatments (alone versus with competition). We excavated whole plants and analyzed their root biomass, root respiration, root system architecture and other related characteristics in each treatment after 100 days.
Important findings Roots of A. sparsifolia grow in the direction where soil space is abundant under no plant competition, even though nutrient patches are present on the opposite side. Roots of A. sparsifolia also grow in the direction where soil space is abundant under plant competition, but neighboring plants limited the development of focal plants, resulting in significantly reduced root and shoot biomass (p < 0.01). Nutrient patches promote the growth of plant roots. The growth of A. sparsifolia roots needs both nutrients and soil space, and space is more important than nutrients. If neighbors are present, plant roots first occupy the space where competitors exist.

Key words: Alhagi sparsifolia, plant competition, root system, soil heterogeneity