title: Photosynthesis of Quercus suber is affected by atmospheric NH3 generated by multifunctional agrosystems.
abstract: Montados are evergreen oak woodlands dominated by Quercus species, which are considered to be key to biodiversity conservation and ecosystem services. This ecosystem is often used for cattle breeding in most regions of the Iberian Peninsula, which causes plants to receive extra nitrogen as ammonia (NH(3)) through the atmosphere. The effect of this atmospheric NH(3) (NH(3atm)) on ecosystems is still under discussion. This study aimed to evaluate the effects of an NH(3atm) concentration gradient downwind of a cattle barn in a Montado area. Leaves from the selected Quercus suber L. trees along the gradient showed a clear influence of the NH(3) on δ(13)C, as a consequence of a strong limitation on the photosynthetic machinery by a reduction of both stomatal and mesophyll conductance. A detailed study of the impact of NH(3atm) on the photosynthetic performance of Q. suber trees is presented, and new mechanisms by which NH(3) affects photosynthesis at the leaf level are suggested.
authors.affiliation: Molecular Ecophysiology Lab. (LEM), Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, 2780-901 Oeiras, Portugal.
authors.forename: Marta
authors.initials: M
authors.lastname: Pintó-Marijuan
authors.forename: Anabela Bernardes
authors.initials: AB
authors.lastname: Da Silva
authors.forename: Jaume
authors.initials: J
authors.lastname: Flexas
authors.forename: Teresa
authors.initials: T
authors.lastname: Dias
authors.forename: Olfa
authors.initials: O
authors.lastname: Zarrouk
authors.forename: Maria Amélia
authors.initials: MA
authors.lastname: Martins-Loução
authors.forename: Maria Manuela
authors.initials: MM
authors.lastname: Chaves
authors.forename: Cristina
authors.initials: C
authors.lastname: Cruz
mesh_terms: D000383:Agriculture; D000641:Ammonia / Q000494:pharmacology*; D002247:Carbon Isotopes / Q000032:analysis; D017753:Ecosystem; D058503:Mesophyll Cells; D010788:Photosynthesis / Q000502:physiology*; D018515:Plant Leaves / Q000187:drug effects / Q000502:physiology; D054046:Plant Stomata / Q000187:drug effects / Q000502:physiology; D018526:Plant Transpiration / Q000502:physiology*; D029963:Quercus / Q000187:drug effects / Q000502:physiology*; D014197:Trees
chemical_list: D002247:Carbon Isotopes; D000641:Ammonia
keywords: carbon isotopic discrimination; cork oak; mesophyll conductance; stomatal conductance