Abstract:The soluble sugar contents, biomass and the activities of superoxide dismutase (SOD), peroxidase (POD) and ATPase of %Potamogeton malaianus% cultured in media with different N and P concentrations corresponding to oligo-, meso-, ertro- and hypertrophic conditions respectively were analysed. %P. malaianus% in the control experiment (oligotrophic) had significantly higher soluble sugar content and biomass than those in other different N and P treatments. In general, the activities of SOD and ATPase increased ...