title: Variations in allelochemical composition of leachates of different organs and maturity stages of Pinus halepensis.
abstract: We investigated changes in the occurrence of allelochemicals from leachates of different Pinus halepensis organs taking into account the stages of pine stand age (i.e., young < 15-years-old, middle age +/- 30-years, and old > 60-years-old). GC-MS analysis of aqueous extracts revealed approx. 59 components from needles and roots. The major constituents were divided into different phytochemical groups-phenolics (50%), fatty acids (44%), and terpenoids. Further analyses were carried out to characterize the distribution of allelochemicals in different organs and P. halepensis successional stages. Roots and needles had two distinct chemical profiles, while needle leachates were composed mainly of oxygenated terpenoids (e.g., alpha-eudesmol, alpha-cadinol, and alpha-terpineol). Roots mainly contained fatty acids. Needles from young pine stands had the highest content of monoterpenes, suggesting their role as potential allelochemicals that could help young pine stands to establish. Pooling the different functional chemical groups showed that needles and, to a lesser extent, old roots, had higher chemical diversity than the roots of young and medium-aged pines. The highest diversity in phenolic constituents and fatty acids was in young needles (D(chem) = 2.38). Finally, caffeic acid, a compound that has allelopathic properties was found in aqueous extracts at high concentrations in both young needles and old roots. The role of this compound in mediation of biological interactions in P. halepensis ecosystem functioning is discussed.
authors.affiliation: Institut Méditerranéen d'Ecologie et Paléoécologie (IMEP)-UMR CNRS 6116, Equipe DFCV, Aix-Marseille Université, Centre de St. Charles, Case 4, 13331 Marseille Cedex 03, France. catherine.fernandez@univ-provence.fr
authors.forename: Catherine
authors.initials: C
authors.lastname: Fernandez
authors.forename: Yogan
authors.initials: Y
authors.lastname: Monnier
authors.forename: Elena
authors.initials: E
authors.lastname: Ormeño
authors.forename: Virginie
authors.initials: V
authors.lastname: Baldy
authors.forename: Stéphane
authors.initials: S
authors.lastname: Greff
authors.forename: Vanina
authors.initials: V
authors.lastname: Pasqualini
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Mévy
authors.forename: Anne
authors.initials: A
authors.lastname: Bousquet-Mélou
mesh_terms: D005227:Fatty Acids / Q000737:chemistry / Q000302:isolation & purification; D039821:Monoterpenes / Q000737:chemistry / Q000302:isolation & purification; D010636:Phenols / Q000737:chemistry / Q000302:isolation & purification; D010675:Pheromones / Q000737:chemistry* / Q000302:isolation & purification; D028223:Pinus / Q000737:chemistry* / Q000254:growth & development; D018515:Plant Leaves / Q000737:chemistry; D018517:Plant Roots / Q000737:chemistry; D025341:Principal Component Analysis; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D005227:Fatty Acids; D039821:Monoterpenes; D010636:Phenols; D010675:Pheromones; D014874:Water Pollutants, Chemical