title: Morphological response to competition for light in the clonal Trifolium repens (Fabaceae).
abstract: OBJECTIVE
  Plant communities in temperate zones are dominated by clonal plants that can plastically modify their growth characteristics in response to competition. Given that plants compete with one another, and the implications this has for species coexistence, we conducted a study to assess how clonal species morphologically respond to competition for light depending on its intensity and heterogeneity, which are determined by the competitor species.
  
  
  METHODS
  We assessed the morphological response to competition for light of the clonal species Trifolium repens L. by measuring its growth performance, and vertical and horizontal growth traits. We used five competitive environments, i.e., one without competitor and four differing by their competitor species creating different conditions of competition intensity and heterogeneity.
  
  
  RESULTS
  The morphological response of Trifolium repens to competition for light depended on the competitor identity. Competition intensity and heterogeneity, determined by competitor identity, had an interactive effect on most traits. The increase in petiole elongation and specific leaf area due to increased competition intensity was observed only at low to intermediate competition heterogeneity. Competition heterogeneity promoted the elongation of clone connections allowing space exploration.
  
  
  CONCLUSIONS
  Our results demonstrated that the intensity and heterogeneity of competition, which depended on competitor identity, are of primary importance in determining the plastic response of Trifolium repens. This emphasizes that it is important to consider the fine-scale spatial distribution of individuals when studying their interactions within plant communities.
authors.affiliation: UMR CNRS 6553, Ecobio, University of Rennes 1, 263 Avenue du Général Leclerc, Rennes Cedex, France. annekristel.bittebiere@orange.fr
authors.forename: Anne-Kristel
authors.initials: AK
authors.lastname: Bittebiere
authors.forename: Nolwenn
authors.initials: N
authors.lastname: Renaud
authors.forename: Bernard
authors.initials: B
authors.lastname: Clément
authors.forename: Cendrine
authors.initials: C
authors.lastname: Mony
mesh_terms: D000704:Analysis of Variance; D018533:Biomass; D002999:Clone Cells; D008027:Light; D019655:Quantitative Trait, Heritable; D029921:Trifolium / Q000033:anatomy & histology* / Q000528:radiation effects*