The Study Of Several Heavy Metal Ions On The Growth Of Algal Cells

In order to investigate the effect on the eutrophication of surface waters when the concentration of heavy metals was far exceeded in the environ-ment,in Scenedesmus quadricauda and Microcystis flos-aquae for the study,setting different multiples excessive concentration of Cr⁶⁺,Cu²⁺,Zn²⁺and Pb²⁺ referring to the surface water quality standards,analyzing the effect of the four heavy metals on two algae's growth and the tolerance of algae on concentrations of heavy metals exceeding for the algal biomass,the content of chlorophyll and cell activity as evaluation.The main conclusions are as follows:?1?Using Cr⁶⁺ 0.1mg/L as the standard,the MDA content of Scenedes-mus quadricauda was most and the membrane lipid peroxide was enhanced when concentration exceeding 20 times;when the concentration was 5.0mg/L,the synthesis of chill-a was inhibited,the chlorate phenomenon was appeared and algae biomass began to decline.The synthesis of chill-a was suppressed in Microcystis flos-aquae when the concentration of Cr⁶⁺exceeding 5 times.With the increase excessive multiples,the stress effect of activity increased,algal biomass was inhibited when excessive times in-creased to 20.?2?Setting excessive concentration gradient as Cu²⁺ 1.0mg/L for stan-dard,we found that low concentrations of Cu²⁺ began to destroy the integri-ty of algal cells by microscopic observation and activity determination.When concentrations exceeded 1.0 times,the cell chloroplast structure of Scenedesmus quadricauda began to disintegrate,green faded and algal bio-mass dropped.In terms of Microcystis flos-aquae,when the concentration of Cu²⁺ was 0.5 times of the standard,the synthesis of chill-a was prevented,algal biomass was lower than the control group.?3?The concentration of Zn²⁺ in surface water quality standards is 2.0mg/L,synthesis of chill-a in the two algal was blocked at this concen-tration.Microscopy revealed that the cell morphology began mutated,MDA content was the greatest,growth was inhibited in Scenedesmus quadricauda and Microcystis flos-aquae when concentrations exceeding 20 and 2.5 times.?4?The concentration of Pb²⁺ in surface water quality standards is 0.1mg/L,when concentrations exceeded 10 times,synthetic of chill-a con-tent was suppressed in Scenedesmus quadricauda and Microcystis flos-aquae.With the concentration increased,cell membrane structure and function was changed and lipid peroxide aggravated.When the concentra-tion exceeded 20 and 50 times,the growth of Scenedesmus quadricauda and Microcystis flos-aquae was inhibited.From the above results can be drawn:in terms of Scenedesmus quadri-cauda,the tolerance of Cr⁶⁺ is strongest and Cu²⁺ is the worst.Concerned Microcystis flos-aquae,the tolerance of Pb²⁺ is strongest and Cu²⁺ is the worst.Except Pb²⁺,Scenedesmus quadricauda comparisons with Microcys-tis flos-aquae,the tolerance of heavy metal is better than Microcystis flos-aquae's.