Chromium(VI) accumulation and tolerance by Tradescantia pallida: biochemical and antioxidant study.

Tradescantia pallida (Wandering jew)-a succulent perennial herb-was screened to be a potent chromium (Cr) accumulator. Its ability to grow under Cr stress was examined by studying biochemical changes and physiological response of the plant in presence of 5-20 mg L(-1) Cr(VI) concentration in hydroponic environment for up to ca. 90 days. Average Cr(VI) bioaccumulation in plant roots reached about 408 μg g(-1) dry weight (dw) after 30 days and up to 536 μg g(-1)dw after 60 days of culture. Biochemical changes in the plant exposed to Cr(VI) indicated a reduction in the total carbohydrate and protein content. Furthermore, lipid peroxidation, catalase, peroxidase and ascorbate peroxidase activity were measured in different parts of the plant exposed to Cr(VI). Increased activities of these enzymes showed their important role in overcoming the Cr-induced oxidative stress on the plant.