Comparative metal accumulation potential of Potamogeton pectinatus L. and Potamogeton crispus L.: Role of enzymatic and non-enzymatic antioxidants in tolerance and detoxification of metals

• Potamogeton crispus accumulated Cr (6648.12 μg g−1 dw) and Pb (3708.33 μg g−1 dw).
• P. crispus emerged as a better metal accumulator as compared to P. pectinatus.
• Antioxidant enzymes and proline provide metal tolerance in P. crispus.
• P. crispus could be used in removing metals from wastewater.

Potamogeton pectinatus L. and Potamogeton crispus L. were grown hydroponically in nutrient solution under Cu, Cr, Pb and Zn stress at 5 mg l−1 concentrations to evaluate their comparative tolerance and metal accumulation potential. Metal toxicity was evident from a decrease in chlorophyll content, increased malondialdehyde (MDA) and electrolyte leakage. However, activities of antioxidant enzymes (superoxide dismutase, ascorbate peroxidase, and guaiacol peroxidase) and non-ezymatic activity of proline and cysteine noticeably increased particularly under Cr and Pb stress. Results showed that P. crispus exhibited better tolerance to high concentration of Cu, Cr, Pb and Zn and accumulated higher concentration of Pb (6648.12 μg g−1 dw) and Cr (6206.84 μg g−1 dw) as compared to P. pectinatus in its tissues. Therefore, P. crispus could be a better phytoremediator species, which may be exploited for the removal of metals from wastewater.