In this work, the changing effect of different concentrations (0, 0.01, 0.1, 1, 10mM) of hexavalent and trivalent
chromium on different biochemical parameters along with antioxidant enzymes was investigated on water lettuce
(Pistia stratiotes L.) in order to know the possible involvement of this metal in oxidative injury, besides the activities
of antioxidant enzymes leading to biochemical and oxidative aberration induced by elevated concentrations. Both in
roots and shoots, Cr produced a significant increase in enzymic and non-enzymic antioxidants, except in catalase
(CAT) activity where a strong accumulation of hydrogen peroxide was indicated, suggesting an imposition of
oxidative stress. The observation showed an uptake of chromium by P. stratiotes L. as well as increase in activity of
antioxidants, as the concentrations and their duration of treatment increased. The activity of antioxidative enzymes
determined the steady-state levels of ROS in the cell. The augmentation of antioxidative defense plays a key role in
regulating the oxidative stress. This pointed to the possibility in induction of oxidative stress, with the increasing
lipid peroxidation, followed by a differential pattern in antioxidant metabolisms by chromium ions in P. stratiotes L.
