Elevated CO2 may reduce arsenic accumulation in diverse ecotypes of Arabidopsis thaliana

Rising concentrations of atmospheric carbon dioxide CO₂] could, potentially, increase contaminant uptake and the overall efficiency of phytoremediation. To determine the ability of elevated CO₂] to sequester arsenic (As), five Arabidopsis thaliana ecotypes were grown at ambient (～400 µmol mol^?1) and elevated (～800 µmol mol^?1) CO₂ at three levels of As concentration (0, 50, and 110 µM) to determine whether: (a) elevated CO₂ increased the concentration of As in above-ground biomass (AGB), and, (b) the effect of CO₂] on As concentration was ecotype specific. We found that elevated CO₂ significantly increased AGB of A. thaliana, but the extent of biomass stimulation was specific to ecotype. Overall, at the highest As concentration, the relative effect of elevated CO₂] was to reduce both As concentration and As uptake per plant; however, genetic variation was also evident among A. thaliana in regard to phytoextraction of As at current and projected CO₂ levels.