Copper accumulation and biochemical responses of Sesuvium portulacastrum (L.)

Abstract

Sesuvium portulacastrum (L.) is a halophytic phytoremediator plant with potential for significant accumulation of metals and metalloids. The present work evaluatedthe physiological and biochemical responses of Sesuvium plants to copper (Cu) exposure (100–500 μM) for 30 d in field conditions. Plants demonstrated significant copper accumulation that increased with the increase in Cu concentration of the medium (maximum 254 µg g−1 DW at 500 µM). The root dry weight was not significantly affected at 500 μM while shoot dry weight decreased significantly. Total soluble proteins, photosynthetic pigmentsand malondialdehye (MDA) were declined significantly beyond 100 μM after 30 d. Among metabolites and enzymes of thiol metabolism, total non-protein thiols (NP-SH), γ-glutamylcysteine synthetase and glutathione reductase did not show significant effect while cysteine, serine acetyltransferase, and cysteine synthaseshowed a significant decline beyond 100 μM. The level of proline, glycine betaine and total phenolics also showed decreasing trend with the increase in Cu concentration. In conclusion, plantsare potential phytoextractor of Cu but do suffer from the toxic effects of Cu at high concentration of 500 μM. Sesuvium plants therefore appear suitable for use in phytoremediation purpose at low Cu concentrations (100 – 250 μM).