Physiological responses and uptake of heavy metals by Miscanthus sacchariflorus (Maxim.) Benth., an energy plant species, under multiple heavy metals stress

Miscanthus sacchariflorus is a metallophyte suitable for the phytoremediation of mine wastes. However, little is known about the tolerance and accumulation to multiple heavy metals (HMs). So, effects of Cu-Cd-Zn-Pb multiple HMs (C1, C2 and C3) on physiological and metal accumulation of M. sacchariflorus were studied by pot experiment. The results showed that the activities of SOD and POD of M. sacchariflorus leaves increased at low HM concentration (C1), MDA content and plasma membrane permeability decreased, and proline content, photosynthetic pigment content, and biomass of M. sacchariflorus increased to a certain degree. At higher HM concentration (>C1), the photosynthetic pigment content and biomass of M. sacchariflorus decreased, especially at high concentration (C3), the photosynthetic pigment content and biomass decreased almost by 50% compared with control. The activities of SOD and POD decreased significantly (P < 0.05), and CAT activity, proline content, MDA content, and plasma membrane permeability increased significantly (P < 0.05). HMs uptaken were mainly retained in the belowground part of M. sacchariflorus, and only a little was accumulated in the aboveground part. Our results suggest that M. sacchariflorus has strong tolerance and root accumulation under combined pollution and has a certain application potential in the phytostabilization of HM compound contaminated soil.