title: Effects of phosphorus availability and genetic variation of leaf terpene content and emission rate in Pinus pinaster seedlings susceptible and resistant to the pine weevil, Hylobius abietis.
abstract: We studied the effects of phosphorus fertilisation on foliar terpene concentrations and foliar volatile terpene emission rates in six half-sib families of Pinus pinaster Ait. seedlings. Half of the seedlings were resistant to attack of the pine weevil Hylobius abietis L., a generalist phloem feeder, and the remaining seedlings were susceptible to this insect. We hypothesised that P stress could modify the terpene concentration in the needles and thus lead to altered terpene emission patterns relevant to plant-insect signalling. The total concentration and emission rate ranged between 5732 and 13,995 μg·g(-1) DW and between 2 and 22 μg·g(-1) DW·h(-1), respectively. Storage and emission were dominated by the isomers α- and β-pinene (77.2% and 84.2% of the total terpene amount amassed and released, respectively). In both resistant and susceptible families, P stress caused an increase of 31% in foliar terpene concentration with an associated 5-fold decrease in terpene emission rates. A higher terpene content in the leaves implies that the 'excess carbon', available under limiting growth conditions (P scarcity), is allocated to terpene production. Sensitive families showed a greater increase in terpene emission rates with increasing P concentrations, which could explain their susceptibility to H. abietis.
authors.affiliation: Global Ecology Unit CREAF-CEAB-CSIC, Universitat Autònoma de Barcelona, Bellaterra, Spain. js.blanch@creaf.uab.cat
authors.forename: J-S
authors.initials: JS
authors.lastname: Blanch
authors.forename: L
authors.initials: L
authors.lastname: Sampedro
authors.forename: J
authors.initials: J
authors.lastname: Llusià
authors.forename: X
authors.initials: X
authors.lastname: Moreira
authors.forename: R
authors.initials: R
authors.lastname: Zas
authors.forename: J
authors.initials: J
authors.lastname: Peñuelas
mesh_terms: D000818:Animals; D005308:Fertilizers; D010758:Phosphorus / Q000378:metabolism*; D010788:Photosynthesis; D028223:Pinus / Q000235:genetics* / Q000378:metabolism*; D018515:Plant Leaves / Q000737:chemistry*; D018526:Plant Transpiration; D013729:Terpenes / Q000032:analysis*; D055549:Volatile Organic Compounds / Q000378:metabolism; D048889:Weevils
chemical_list: D005308:Fertilizers; D013729:Terpenes; D055549:Volatile Organic Compounds; D010758:Phosphorus