蛋白核小球藻对4种重金属胁迫的响应研究

为了利用藻类对水体重金属进行监测预警,以蛋白核小球藻为指示生物,研究了重金属Cd~(2+)、Cr~(6+)、Mn~(2+)、Pb~(2+)对藻类的抑制作用。实验结果表明:重金属对蛋白核小球藻的抑制作用总体表现为随着重金属浓度的增加和胁迫时间的延长而增加,抑制率一般在0~48 h内迅速增加,随后增长速率有所减缓,至96 h抑制率达到最大。蛋白核小球藻的抑制率与重金属浓度呈现明显的剂量-效应关系;与吸光度、叶绿素相对含量的变化相比,F_v/F_m对重金属胁迫的响应变化最为稳定和敏感,因此更适合作为检测指标监测重金属。从EC_(50)值的比较看,Cd~(2+)对蛋白核小球藻的毒性最大,其次是Cr~(6+)和Pb~(2+),Mn~(2+)的毒性最小。

Responses of Chlorella pyrenoidesa to stress of four heavy metals

To monitor and early warn heavy metals in water by algae, we chose Chlorella pyrenoidesa as bioindicator to study its response to stress of four heavy metals Cd2+, Cr6+, Mn2+, Pb2+.It shows that the inhibition on Chlorella pyrenoidesa increases with the increase of metal concentration and reaction time in general. The inhibition rate rises sharply in 0~48 h. Thereafter, it rises slowly to the peak at 96 h. The inhibition rate of Chlorella pyrenoidesa and the heavy metal concentration demonstrates a does-effect relationship. Compared with the variation of the relative amount of absorption and chlorophyll, the response of Fv/Fm to stress of heavy metals is more stable and sensitive. Thus, it is more suitable to be the detection index. The EC50shows, the toxicity of Cd2+ to Chlorella pyrenoidesa is the highest, followed by Cr6+ and Pb2+, and Mn2+ is the lowest.