含氯化镉水体中螺旋藻的生长及其对镉的摄取作用

研究了钝顶螺旋藻和极大螺旋藻在含CdCl2水体中的生长状况与摄Cd能力.结果表明:两种螺旋藻皆对CdCl2有较强的耐受能力,但是有不同的摄Cd行为.当CdCl2浓度为6~24mg.L-1,培养96h时,两种螺旋藻对Cd的摄取作用主要表现为藻细胞外的表面吸附;培养10d时,钝顶螺旋藻的胞内Cd含量依然甚微,而极大螺旋藻对Cd的细胞内吸附量却明显增加,24mg.L-1CdCl2处理的极大螺旋藻胞内的Cd吸附量为12mg.L-1CdCl2处理的11.6倍,且略超过细胞表面吸附量.表明在高浓度Cd的长时间胁迫下,两种螺旋藻的摄Cd行为和对Cd的耐受机制具有明显差异,其中钝顶螺旋藻为胞外机制,而极大螺旋藻却为胞内、胞外混合机制,且以胞内机制为主.

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.