Cd(Ⅱ)对小球藻生长抑制和恢复研究

Study on Cd(Ⅱ) on the Growth Inhibition and Recovery of Chlorella

重金属与小球藻相互作用的研究是认识和评估利用小球藻治理重金属污染有效性及生态风险的重要依据。该文通过序批式实验考察小球藻对重金属Cd的吸附行为,同时探究Cd胁迫对小球藻生长规律的影响。首先,实验结果表明小球藻对重金属的吸附是一个快速完成的过程,但随着Cd(Ⅱ)浓度的增大,其吸附平衡时间越长;其次,随着Cd(Ⅱ)浓度增大,对小球藻生长的抑制呈现逐渐增大的趋势,5 mg/L Cd(Ⅱ)胁迫下,小球藻对数期的5 d平均增长率相比对照减少了78.23%;再次,洗去胞外重金属后,小球藻处理组的生长速率均有恢复,5 mg/L Cd(Ⅱ)恢复期的5 d平均增长率相比对照增加了190%;最后通过透射电镜观察小球藻亚细胞结构发现经过5 d的恢复期有部分细胞器得到了恢复。

The study of the interaction between heavy metals and Chlorella is an important basis for understanding and evaluating the effectiveness of using Chlorella to treat heavy metal pollution and ecological risks. This study investigates the adsorption behavior of Chlorella to heavy metal Cd through sequencing batch experiments, and at the same time explores the effect of Cd stress on the growth of Chlorella. The experimental results show that the adsorption of heavy metals by Chlorella is a rapid process, but as the concentration of Cd(Ⅱ) increases, the adsorption equilibrium time becomes longer. As the concentration of Cd(Ⅱ) increases, the inhibition of the growth of Chlorella showed a gradually increasing trend. Under the stress of 5 mg/L Cd(Ⅱ), the 5-day average growth rate of the logarithmic phase of Chlorella decreased by 78.23% compared with the control. The extracellular heavy metals were washed away, and the growth rate of the Chlorella treatment group was recovered. The growth rate during the recovery period of 5 mg/L Cd(Ⅱ) increased by 190% compared with the control.Finally, the subcellular structure of Chlorella was observed by transmission electron microscope(TEM), and it was found that after a 5-day recovery period, some organelles were recovered.