砷对铜绿微囊藻生长率影响的研究

The Effect of Arsenate on the Growth Rate of Microcystis aeruginosa

采用磷饥饿培养后的铜绿微囊藻FACHB905进行不同浓度砷(V)和磷的暴露试验,考察砷、磷并存对滇池分离出的铜绿微囊藻生长率的影响。结果表明,磷在一定浓度范围内(≤40μg/L),外源性磷是微囊藻生长的制约因子。磷浓度变化不影响铜绿微囊藻FACHB905对砷(V)的耐受阈值,阈值均值为106.5μg/L,EC50,48h值随着磷浓度的升高而增大。由上可知,低浓度砷(V)不影响磷酸盐动力学参数,从侧面反映出铜绿微囊藻FACHB905对砷和磷具有一定的分辨能力。这对于砷背景值较高的滇池水域中微囊藻水华暴发过程研究具有一定的参考价值。

Exposure of arsenate on Microcystis aeruginosa FACHB905 preconditioned to phosphate starvation was performed under different phosphate regimes.It was designed to explore the effects of arsenate and phosphate on the growth rate of M.aeruginosa FACHB905 isolated from Dianchi Lake when the extracellular phosphate or arsenate concentration was changeable.The results showed that the growth rates increased along with the increase additional amount of phosphate in the medium when the phosphate concentration lower than 40 μg/L,was the limited factor for the cyanobacterial growth.It was shown that the extracellular phosphate concentration had no reference to the threshold doses of M.aeruginosa FACHB905 to arsenate,and the threshold doses was 106.5μg/L,however,the EC50,48h value increased along with the increase phosphate concentration.In this study,arsenate had no effect on the parameters of phosphate uptake kinetics,which gave some evidence indirectly that M.aeruginosa FACHB905 had the ability of discriminating between phosphate and arsenate.It was found most helpful on complete understanding of microcystis bloom formation in Dianchi Lake with high environmental background values of arsenic.