title: Rising CO2from historical concentrations enhances the physiological performance of Brassica napus seedlings under optimal water supply but not under reduced water availability.
abstract: The productivity of many important crops is significantly threatened by water shortage, and the elevated atmospheric CO2can significantly interact with physiological processes and crop responses to drought. We examined the effects of three different CO2concentrations (historical ~300 ppm, ambient ~400 ppm and elevated ~700 ppm) on physiological traits of oilseed rape (Brassica napus L.) seedlings subjected to well-watered and reduced water availability. Our data show (1) that, as expected, increasing CO2level positively modulates leaf photosynthetic traits, leaf water-use efficiency and growth under non-stressed conditions, although a pronounced acclimation of photosynthesis to elevated CO2occurred; (2) that the predicted elevated CO2concentration does not reduce total evapotranspiration under drought when compared with present (400 ppm) and historical (300 ppm) concentrations because of a larger leaf area that does not buffer transpiration; and (3) that accordingly, the physiological traits analysed decreased similarly under stress for all CO2concentrations. Our data support the hypothesis that increasing CO2concentrations may not significantly counteract the negative effect of increasing drought intensity on Brassica napus performance.
authors.affiliation: Department of Crop and Environment Sciences, Harper Adams University, Newport, Shropshire, TF10 8NB, UK.
authors.forename: Michele
authors.initials: M
authors.lastname: Faralli
authors.affiliation: Department of Crop and Environment Sciences, Harper Adams University, Newport, Shropshire, TF10 8NB, UK.
authors.forename: Ivan G
authors.initials: IG
authors.lastname: Grove
authors.affiliation: Department of Crop and Environment Sciences, Harper Adams University, Newport, Shropshire, TF10 8NB, UK.
authors.forename: Martin C
authors.initials: MC
authors.lastname: Hare
authors.affiliation: Department of Crop and Environment Sciences, Harper Adams University, Newport, Shropshire, TF10 8NB, UK.
authors.forename: Peter S
authors.initials: PS
authors.lastname: Kettlewell
authors.affiliation: IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, Jülich, Germany.
authors.forename: Fabio
authors.initials: F
authors.lastname: Fiorani
mesh_terms: D029688:Brassica napus / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D002244:Carbon / Q000378:metabolism; D002245:Carbon Dioxide / Q000494:pharmacology*; D055864:Droughts; D018515:Plant Leaves / Q000187:drug effects / Q000502:physiology; D018526:Plant Transpiration / Q000187:drug effects / Q000502:physiology; D036226:Seedlings / Q000187:drug effects / Q000502:physiology*; D014867:Water / Q000502:physiology*
chemical_list: D014867:Water; D002245:Carbon Dioxide; D002244:Carbon
keywords: Canola; climate change; elevated CO2; evapotranspiration; leaf area; photosynthesis; shoot biomass; stomatal conductance