Pb2+胁迫对绿球藻(Chlorococcum sp.)的影响研究

研究了不同Pb²⁺浓度(0.1、1、10、50、100、200、400 mg/L)处理对绿球藻(Chlorococcum sp.)生长、形态结构及生理特性的影响。与对照BG11培养的绿球藻比较,Pb²⁺浓度≤50 mg/L条件下培养的绿球藻细胞壁无明显增厚,色素变化不大;而暴露到Pb²⁺浓度>50 mg/L条件下培养,绿球藻细胞壁明显增厚,蛋白核消失。低浓度Pb²⁺(0.1~10 mg/L)对绿球藻生长基本没有影响;浓度在50 mg/L时,绿球藻仍能维持一定的生长速率;但当Pb²⁺浓度≥100 mg/L时,绿球藻的生长受到显著抑制。绿球藻的Chl a+Chl b以及Chl a含量均随培养基中Pb²⁺浓度的升高而逐渐减少。绿球藻净光合作用强度随培养基中Pb²⁺浓度的增大而逐渐降低,Pb²⁺浓度≥100 mg/L时净光合作用强度检测不到;当Pb²⁺浓度<50 mg/L时,绿球藻呼吸作用强度逐渐升高,之后呼吸作用强度逐渐降低。在实验的浓度下,绿球藻的丙二醛(MDA)含量、超氧化物歧化酶(SOD)和过氧化物酶(POD)活性都随培养基中Pb²⁺浓度的升高而逐渐增强;过氧化氢酶(CAT)则随Pb²⁺浓度的增大酶活性先升高后降低。当Pb²⁺浓度≤100 mg/L时,绿球藻对Pb²⁺的去除率都在95%以上;之后逐渐降低,浓度到400 mg/L时仍然达56.7%。结果显示,绿球藻是一种耐受Pb²⁺胁迫的藻类,对铅的去除率也高,可以应用于含铅污水的处理。

The Effects of Pb2+ Stress on Chlorococcum sp.

The effects of different concentration Pb²⁺(0.1,1,10,50,100,200,400 mg/L)in BG11 on the growth,morphostructure and physiological characteristics of Chlorococcum sp.were studied.Compared with the cell cultured in BG11,the cell cultured in low concentrations(≤50 mg/L)showed few changes in pigment and thickness of cell wall;the cell wall of the cell cultured in high concentrations of Pb²⁺(>50 mg/L)became thicker,and the pigment decreased and the pyrenoid disappeared.When the concentrations of Pb²⁺ were 0.1-10 mg/L,the growth of Chlorococcum sp.showed no obvious difference compared with the control;when the concentration of Pb²⁺ was 50 mg/L,Chlorococcum sp.could maintain certain growth rate yet;however,when the concentration of Pb²⁺ was higher than 100 mg/L,the growth of Chlorococcum sp.was inhibited markedly.The contents of Chl a+Chl b or Chl a decreased gradually with the increase of the concenrations of Pb²⁺ in the medium.The photosynthesis of Chlorococcum sp.decreased gradually with the increase of Pb²⁺ concentrations,when the concentration of Pb²⁺ was higher than 100 mg/L,the photosynthesis of Chlorococcum sp.could not be detected;when the concentration of Pb²⁺ was less than 50 mg/L,the respiration of Chlorococcum sp.increased gradually with the increase of Pb²⁺ concentrations,and when the concentration of Pb²⁺ was higher than 50 mg/L,they decreased gradually with the increase of Pb²⁺ concentrations.The content of malondiadehyde and activities of superoxide dismutase and peroxidase increased gradually with the increase of Pb²⁺ concentrations,and the activity of catalase increased at beginning and then decreased with the increase of Pb²⁺ concentrations.When the concentration of Pb²⁺ was ≤100 mg/L,the removal rate of Chlorococcum sp.on Pb²⁺ was >95%,and it was up 56.7% yet when the concentration of Pb²⁺ was 400 mg/L.The results demonstrated that the Chlorococcum sp.could be applied to the treatment of wastewater containing Pb²⁺,because the Chlorococcum sp.could endure the stress of Pb²⁺ and was of high removal rate on Pb²⁺.