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 (approximate to 400 mu mol mol(-1)) and elevated (approximate to 800 mu mol mol(-1)) CO2 at three levels of As concentration (0, 50, and 110 mu M) 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.