Cynara cardunculus a potentially useful plant for remediation of soils polluted with cadmium or arsenic

Cynara cardunculus can be grown as high biomass crop for energy or biofuel. Marginal land rather than farmland should be used for such crops. Here we evaluated the tolerance of Cynara plants to Cd and As using controlled-environment conditions and hydroponic culture. The aim was to ascertain whether this species could be potentially useful for phytoremediation of marginal soils with excess Cd or As burdens. Plants were exposed to 5 mu M Cd or to 5 or 10 mu M As in the form of arsenate or arsenite. Root elongation, malonyldialdehyde production and total concentrations of total acid soluble thiols were used as indicators of stress response. Biomass production and root and shoot accumulation of Cd and As were determined. The plants exhibited considerable tolerance to Cd and As. Biomass was hardly affected by the potentially toxic concentrations of Cd and As. Cadmium was preferentially accumulated in old leaves. Contrastingly, As was efficiently retained in the roots. Results indicate that C. cardunculus can be a useful species for phytoextraction of Cd from polluted soils. On soils rich in arsenic, cardoon could be grown as an energy crop that can help to stabilize these soils. (C) 2012 Elsevier B.V. All rights reserved.