实验室条件下Hg^(2+)胁迫对集球藻生理生化特性的影响

Study on the physiological and biochemical properties of Palmellococcus sp. subjected to Hg2+ stress in laboratory condition

重金属污染是当今世界最为关注的生态环境问题之一。在实验室条件下,以一种从荒漠土壤中分离的单细胞绿藻———集球藻(Palmellococcus sp.)为试验材料,研究Hg2+胁迫对集球藻生理生化特性的影响。结果表明:与对照相比,Hg2+胁迫明显抑制了集球藻的生长和光合活性,表现为藻体生物量(叶绿素a)和叶绿素荧光参数(Fv/Fm)均发生显著性下降。随Hg2+胁迫剂量加大,集球藻细胞内可溶性糖出现一定程度的积累,而Hg2+胁迫明显抑制细胞内可溶性蛋白质的合成。集球藻细胞抗氧化活性的测定结果表明,Hg2+胁迫导致集球藻细胞MDA含量明显升高,SOD和CAT活性亦呈现增大的变化趋势。研究结果对于更好地理解荒漠土壤绿藻对重金属胁迫的耐受性及其适应机制提供了有意义的参考。

Heavy metal pollution is one of the most common ecological and environmental problems faced in current world. In this study, we selected one species of single cellular green alga, Palmelloeoccus sp. , separated from desert soil, as experimental material to investigate the effect of Hg2 ＋ stress on its physiological and biochemical properties in laboratory condition. Our results showed that Hg2 ＋ stress obviously inhibited the growth and photosynthetic activity of Palmelloeoccus sp. There were evident decreases in biomass （chlorophyll a） and chlorophyll fluorescence parameter （Fv/Fm） of the treated cells compared to the control cells. It also indicated that the soluble saccharide content of the treated algal cells present accumulation to some extent along with Hg2 ＋ concentration addition, while Hg2 ＋ stress evi- dently restrained the synthesis of cellular soluble protein of Palmelloeoecus sp. The results from examination of antioxidant activities of Palmellococcus sp. subjected to Hg2 ＋ treatments validated that Hg2 ＋ stress had a significantly deleterious effect on membrane lipid superoxide as assessed by measurement of MDA content, and SOD and CAT activities also pres- ented obvious increases as compared to the control. The study provided a better understanding for the endurance and physiological adaptation of desert soil green algae to heavy metal pollution.