Investigation of chromium phytoremediation and tolerance capacity of a weed, Portulaca oleracea L. in a hydroponic system

The present investigation was undertaken to study the growth, biomass, physiological‐biochemical responses and chromium (Cr) accumulation capacity of hydroponically grown Portulaca oleracea cuttings exposed to Hoagland solution supplemented with Cr(VI) (0.0, 0.1, 0.5, 1.0, 2.5, 5.0, 10 mg/L) for 30 days. The cuttings exhibited effective regeneration in Hoagland solution in comparison to deionized water. Plants demonstrated significant reduction in growth (root and shoot length, leaf area), biomass (root and shoot dry weight), pigments (total chlorophylls and carotenoids) and total soluble sugar content at higher concentration of Cr(VI) (10 mg/L). However, plants could tolerate Cr stress through significantly higher accumulation of proline and increased activity of peroxidase resulting in significant Cr accumulation (150–190 mg/kg dry weight) in harvestable parts of Portulaca. Thus, the results suggest application of P. oleracea for phytoremediation of Cr‐contaminated sites for the protection of environment.