[Growth and cd uptake of Spirulina in water body containing CdCl2]

The study on the growth and Cd uptake of Spirulina platensis and S. maxima in the water body containing different concentrations of CdCl2 showed that these two species of Spirulinas had high tolerance to CdCl2 but differed in their characters of Cd-uptake. When the concentration of CdCl2 was from 6 mg L(-1) to 24 mg x L(-1), the Cd uptake of these two species at their early growth stage (within 96 h) was mainly through extracellular adsorption. After 10 days of growth, the intracellular Cd content was still negligible in S. platensis, but obviously increased in S. maxima, being 11.6 times higher in treatment 24 mg CdCl2 x L(-1) than in treatment 12 mg CdCl2 x L(-1), and slightly higher than extracellular Cd content, which suggested that under long-term high concentration Cd stress, S. platensis and S. maxima had different mechanisms of Cd uptake and Cd tolerance, i. e., S. platensis had an extracellular mechanism, while S. maxima had both extracellular and intracellular mechanisms and gave priority to intracellular mechanism.