Cd^(2+)胁迫条件下椭圆小球藻的生理应答  

PHYSICAL RESPONSES TO Cd^(2+) STRESS IN CHLORELLA ELLIPSOIDEA

作　　者：李建宏[1] 浩云涛[1] 翁永萍[1] 

机构地区：[1]南京师范大学生命科学学院,南京210097

出　　处：《水生生物学报》2004年第6期659-663,共5页Acta Hydrobiologica Sinica

基　　金：教育部留学归国人员基金 (2 0 0 3 );江苏省教育厅自然基金资助 (2 0 0 3 )

摘　　要：研究了一株高重金属抗性的椭圆小球藻在Cd2 + 胁迫下的生理变化 ,结果显示 ,在 10— 2 4 0 μmol/L浓度的Cd2 +胁迫下 ,随着金属离子浓度提高 ,叶绿素的总量减少 ,光合放氧受到抑制。Cd2 + 离子浓度的提高 ,导致了氧自由基的大大增加 ,同时脯氨酸、SOD(超氧化物歧化酶 )以及POD(过氧化物酶 )水平均大大提高。结果提示这些与消除自由基有关的代谢产物的积累 ,有利于细胞减少胁迫造成的损伤。CAT(过氧化氢酶 )对Cd2 + 离子是敏感的 。A high heavy metal resistant Chlorella ellipsoidea strain was isolated from the electroplating waste water.Former researches had showed the alga had high tolerance to heavy metals and was able to eliminate Cu 2+ ,Zn 2+ ,Ni 2+ and Cd 2+ effectively from water.So it could be used for decreasing heavy metal pollution.To understand the physical mechanisms of the alga against the toxicities of heavy metals,we studied the physical responses of the alga to Cd 2+ stress.In this research,we focused on the physical reactions to radical injuring in cells caused by Cd 2+ . Methods:Photosynthesis O 2 release was measured by membrane oxygen electrode;Superoxide anion radical was measured by xanthine oxidase and NBT system;Superoxide dismutase (SOD) activity is determined by hydroxylamine assay-developed from xanthine oxidase assay;Catalase(CAT)was measured by molybdic acid method;Peroxidase(POD)was determined by method of guaiacol oxidation;Proline was measured by the method of Sulosalicylic acid. Results:Chlorophyll content and photosynthetic O 2 release were measured as indicators of cadmium toxicities.Results showed that,between 10 to 240μmol/L Cd 2+ ,total chlorophyll content and photosynthesis O 2 release decreased when the ion concentration increased.The lower concentration of Cd 2+ ,10μmol/L induced higher chlorophyll-a,it was 130% of the control.Cadmium caused the ratio of chlorophyll-a/b rising. When Cd 2+ was over 30μmol/L,the ratio of chla/b rose from 1 22 to 2 61 These showed Cd 2+ in this concentration range could cause toxicities to the C.ellipsoidea. So this concentration range of Cd 2+ was used as stress to induce radicals and observe the physical responses of the alga.Results showed Cd 2+ produced more O 2-. in algal cells.When Cd 2+ was 90μmol/L,O 2-. was 2.07 times as much as the control in 72hrs after incubated.Meanwhile,POD was induced strongly and reached the highest level.It's content was 4.84 times concentration of th

关 键 词：重金属 抗性 CD^2+ 镉 自由基 椭圆小球藻 生理应答 

分 类 号：Q949.2[生物学—植物学]