Chin J Plant Ecol ›› 2007, Vol. 31 ›› Issue (4): 665-672.DOI: 10.17521/cjpe.2007.0086

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SHEN Rui-Ling1,2, GUAN Bao-Hua1,2, CAI Ying1,2, AN Shu-Qing1,2,*(), JIANG Jin-Hui1,2, DONG Lei3   

  1. 1The State Key Laboratory of Pollution Control and Resource Reuse, School of Life Sciences, Nanjing University, Nanjing 210093, China
    2Institute of Wetland Ecology, Nanjing University, Nanjing 210093, China
    3South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
  • Received:2006-07-19 Accepted:2007-01-05 Online:2007-07-19 Published:2007-07-30
  • Contact: AN Shu-Qing


Aims Plants show phenotypic plasticity in response to changing environments via variations of morphological and ecophysiological traits, and this plasticity can increase invasiveness. Plasticity, rather than genetic diversity, made Alternanthera philoxeroides more invasive, but its plasticity to sediment phosphorus concentration of invaded habitats was undocumented. This study addresses plasticity of A. philoxeroides to sediment phosphorus concentration and planting density and whether plasticity increases invasiveness.
Methods In a controlled factorial experiment, we grew artificial populations of A. philoxeroides at low and high densities (four and eight individuals per container, respectively) under three levels (low, median, high) of sediment phosphorus concentrations. All plants were harvested after six weeks, and dry mass of leaves, stems and roots were measured.
Important findings Under low planting density, leaf mass and number, stem mass and length, branch number, and total biomass of A. philoxeroides were larger at high than low or median sediment phosphorus concentration. Under high planting density, leaf number, stem length and special stem length were greater at high than at low or median sediment phosphorus concentration. Leaf, stem, root and total phosphorus concentrations in A. philoxeroides increased significantly with increasing the sediment phosphorus concentration. Leaf mass ratio was also affected by sediment phosphorus concentration, and stem mass, special stem length, leaf and total phosphorus concentration were significantly affected by planting density. Results imply that morphological and ecophysiological traits of A. philoxeroides were altered by sediment phosphorus concentration and that high sediment phosphorus may strengthen the invasiveness of A. philoxeroides.

Key words: phenotypic plasticity, sediment phosphorus, planting density, invasiveness, clonal growth, Alternanthera philoxeroides