title: Differences in volatile terpene composition between the bark and leaves of tropical tree species.
abstract: Volatile terpenes are among the most diverse class of defensive compounds in plants, and they are implicated in both direct and indirect defense against herbivores. In terpenes, both the quantity and the diversity of compounds appear to increase the efficiency of defense as a diverse blend of compounds provides a more efficient protection against a broader range of herbivores and limits the chances that an enemy evolves resistance. Theory predicts that plant defensive compounds should be allocated differentially among tissues according to the value of the tissue, its cost of construction and the herbivore pressure on it. We collected volatile terpenes from bark and leaves of 178 individual tree belonging to 55 angiosperm species in French Guiana and compare the kind, amount, and diversity of compounds in these tissues. We hypothesized that in woody plants, the outermost part of the trunk should hold a more diverse blend of volatile terpenes. Additionally, as herbivore communities associated with the leaves is different to the one associated with the bark, we also hypothesized that terpene blends should be distinct in the bark vs. the leaves of a given species. We found that the mixture of volatile terpenes released by bark is different and more diverse than that released by leaves, both in monoterpenes and sesquiterpenes. This supports our hypothesis and further suggests that the emission of terpenes by the bark should be more important for trunk defense than previously thought.
authors.affiliation: Laboratoire Evolution et Diversité Biologique, UMR 5174 CNRS/Université Paul Sabatier, 118 route de Narbonne, Toulouse, France.
authors.forename: Elodie A
authors.initials: EA
authors.lastname: Courtois
authors.forename: Christopher
authors.initials: C
authors.lastname: Baraloto
authors.forename: C E Timothy
authors.initials: CE
authors.lastname: Paine
authors.forename: Pascal
authors.initials: P
authors.lastname: Petronelli
authors.forename: Pierre-Alain
authors.initials: PA
authors.lastname: Blandinieres
authors.forename: Didier
authors.initials: D
authors.lastname: Stien
authors.forename: Emeline
authors.initials: E
authors.lastname: Höuel
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Bessière
authors.forename: Jérôme
authors.initials: J
authors.lastname: Chave
mesh_terms: D024301:Plant Bark / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry*; D013729:Terpenes / Q000032:analysis*; D014197:Trees / Q000737:chemistry*; D014329:Tropical Climate; D014835:Volatilization
chemical_list: D013729:Terpenes