[Protective effects of exogenous ascorbic acid on antioxidant system in Hydrilla verticillata under Cd2+]

In this paper, Hydrilla verticillata was cultured in the hoagland solution containing 5 mg L(-1) Cd2+ and different concentration ascorbic acid (AsA) to investigate the protective action of AsA to aquatic plant suffered from heavy metal's stress. The O2 generation rate, H2O2 content, antioxidants (AsA and GSH) contents, and antioxidant enzymes (SOD, POD, CAT and APX) activities were analyzed. The results showed that compared with single Cd2+ treatment, AsA addition lessened the reactive oxygen species (O2-* and H2O2) generation rates, endogenous AsA content, and antioxidant enzyme activities. It was concluded that exogenous AsA could relieve the Cd2+ poison to H. verticillata, and its optimum concentration was 60 mg x L(-1).