title: Interaction of 8-hydroxyquinoline with soil environment mediates its ecological function.
abstract: BACKGROUND
  Allelopathic functions of plant-released chemicals are often studied through growth bioassays assuming that these chemicals will directly impact plant growth. This overlooks the role of soil factors in mediating allelopathic activities of chemicals, particularly non-volatiles. Here we examined the allelopathic potential of 8-hydroxyquinoline (HQ), a chemical reported to be exuded from the roots of Centaurea diffusa.
  
  
  RESULTS
  Growth bioassays and HQ recovery experiments were performed in HQ-treated soils (non-sterile, sterile, organic matter-enriched and glucose-amended) and untreated control soil. Root growth of either Brassica campestris or Phalaris minor was not affected in HQ-treated non-sterile soil. Soil modifications (organic matter and glucose amendments) could not enhance the recovery of HQ in soil, which further supports the observation that HQ is not likely to be an allelopathic compound. Hydroxyquinoline-treated soil had lower values for the CO(2) release compared to untreated non-sterile soil. Soil sterilization significantly influenced the organic matter content, PO(4)-P and total organic nitrogen levels.
  
  
  CONCLUSIONS
  Here, we concluded that evaluation of the effect of a chemical on plant growth is not enough in evaluating the ecological role of a chemical in plant-plant interactions. Interaction of the chemical with soil factors largely determines the impact of HQ on plant growth.
authors.affiliation: Department of Environmental Biology, University of Delhi, Delhi, India. inderjit@cemde.du.ac.in
authors.lastname: Inderjit
authors.forename: Devika
authors.initials: D
authors.lastname: Bajpai
authors.forename: M S
authors.initials: MS
authors.lastname: Rajeswari
mesh_terms: D001937:Brassica / Q000187:drug effects / Q000254:growth & development*; D017753:Ecosystem; D015125:Oxyquinoline / Q000494:pharmacology*; D031783:Phalaris / Q000187:drug effects / Q000254:growth & development*; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D012987:Soil / Q000032:analysis*; D012988:Soil Microbiology
chemical_list: D012987:Soil; D015125:Oxyquinoline