Physiological and biochemical effects of different doses of selenium on Spirulina platensis

The physiological and biochemical effects of different doses of Se(IV) on S. platensis were investigated in this study by adding Se(IV) everyday to maintain the Se dose atinvariable levels during the growth of S. platensis. Seadding quantity perbiomass of S. platensis was defined to be Se dose(x_Se = CSe/W). The results showed that the activities of antioxidases in S. platensis were increased with Sedoses increasing except APX;the Se has stimulative effects to the growth of S. platensis and the concentrations of pigments and water soluble proteins in S. platensis were higher than those of the control when x_Se≤0.1, the concentrations of MDA were less or close to that of the control;the concentrations of pigments and water soluble proteins dropped obviously when x_Se≥0.2, and the biomass of S. platensis was decreased by 21% when Se dose was increased to 0.4. Moreover, the concentrations of MDA increased obviously with the x_Se increasing. These results indicated that Se(IV) was nutrient to S. platensis when x_Se≤0.1 and toxic to S. platensis when x_Se≥0.2.