title: Response to multi-generational selection under elevated [CO2] in two temperature regimes suggests enhanced carbon assimilation and increased reproductive output in Brassica napus L.
abstract: Functional plant traits are likely to adapt under the sustained pressure imposed by environmental changes through natural selection. Employing Brassica napus as a model, a multi-generational study was performed to investigate the potential trajectories of selection at elevated [CO2] in two different temperature regimes. To reveal phenotypic divergence at the manipulated [CO2] and temperature conditions, a full-factorial natural selection regime was established in a phytotron environment over the range of four generations. It is demonstrated that a directional response to selection at elevated [CO2] led to higher quantities of reproductive output over the range of investigated generations independent of the applied temperature regime. The increase in seed yield caused an increase in aboveground biomass. This suggests quantitative changes in the functions of carbon sequestration of plants subjected to increased levels of CO2 over the generational range investigated. The results of this study suggest that phenotypic divergence of plants selected under elevated atmospheric CO2 concentration may drive the future functions of plant productivity to be different from projections that do not incorporate selection responses of plants. This study accentuates the importance of phenotypic responses across multiple generations in relation to our understanding of biogeochemical dynamics of future ecosystems. Furthermore, the positive selection response of reproductive output under increased [CO2] may ameliorate depressions in plant reproductive fitness caused by higher temperatures in situations where both factors co-occur.
authors.affiliation: Department of Chemical and Biochemical Engineering, Technical University of Denmark, Risø Campus Frederiksborgvej 399, 4000, Roskilde, Denmark ; Department of Biosciences, Plant Biology, Aarhus University Ole Worms Allé 1, DK-8000, Aarhus C, Denmark.
authors.forename: Georg
authors.initials: G
authors.lastname: Frenck
authors.forename: Leon
authors.initials: L
authors.lastname: van der Linden
authors.forename: Teis Nørgaard
authors.initials: TN
authors.lastname: Mikkelsen
authors.forename: Hans
authors.initials: H
authors.lastname: Brix
authors.forename: Rikke Bagger
authors.initials: RB
authors.lastname: Jørgensen
keywords: Carbon dioxide; experimental evolution; global change; laboratory natural selection; oilseed rape; phenotypic divergence; plant-environment feedbacks