二价铁对铜绿微囊藻和栅藻细胞生长的影响及机理  

Effects and Their Mechanisms of Fe^(2+)on Cell Growth of Microcystis aeruginosa and Scenedesmus sp.

作　　者：李雁宜 王利 马徐发[1] Li Yanyi;Wang Li;Ma Xufa(College of Fisheries,Huazhong Agricultural University,Wuhan 430070,China)

机构地区：[1]华中农业大学水产学院,武汉430070

出　　处：《生态毒理学报》2024年第5期296-308,共13页Asian Journal of Ecotoxicology

基　　金：国家自然科学基金青年项目(32301357)。

摘　　要：铁磷相互作用影响藻类生长,但铁变化对藻类胞内外磷赋存和铁吸收的影响机制还不清楚。本研究选择湖泊水华代表种铜绿微囊藻(Microcystis aeruginosa)及其竞争优势种栅藻(Scenedesmus sp.)为研究对象,设置了5个二价铁(Fe^(2+))浓度处理组(0.00、0.05、0.50、1.00和1.50 mg·L^(-1))。测量了不同铁浓度下藻类细胞密度和微藻胞内外磷浓度及其胞外分泌物包括胞外聚合物(extracellular polymeric substances phosphorus,EPS)和铁载体浓度的变化,探究二价铁浓度变化如何通过胞外分泌物影响微藻磷吸收赋存和铁吸收的过程。研究结果显示,2种微藻细胞密度最适生长的二价铁浓度不同,1.00 mg·L^(-1)时利于铜绿微囊藻生长,0.05 mg·L^(-1)时利于栅藻生长。铜绿微囊藻胞内磷及胞内铁结合态磷浓度与二价铁浓度呈正相关性。铜绿微囊藻和栅藻的胞外磷浓度均与二价铁浓度呈负相关性。添加二价铁1 d后,二价铁浓度与2种微藻胞外EPS蛋白均呈正相关性,与EPS多糖呈负相关性。第14天时,1.50 mg·L^(-1)二价铁浓度下2种微藻分泌的EPS蛋白浓度最高,分别为21.12 mg·L^(-1)和19.19 mg·L^(-1)。结果表明,在低浓度二价铁下2种微藻会瞬时分泌更多的铁载体吸收铁,和通过分泌胞外EPS多糖形式吸收胞外磷。在高浓度二价铁下,有利于2种微藻叶绿素a的产量和铁结合态磷的积累;且铜绿微囊藻将胞外磷转化为胞内磷的效率高于栅藻。本研究可为湖泊富营养化治理过程中阻断沉积物中内源磷对藻类生长的供给循环提供理论指导意义。The interaction of iron and phosphorus affects phytoplankton growth,but the mechanism of iron change on the phosphorus(P)allocation of algal cells and iron absorption is still unclear.To explore how the change of Fe^(2+)concentration affects the process of P allocation and iron absorption in microalgae through extracellular secretions,this study selected Microcystis aeruginosa and Scenedesmus sp.The Fe^(2+)concentration among treatment groups was 0.00,0.05,0.50,1.00 and 1.50 mg·L^(-1).The cell density of algae,changes in their P forms,content,and distribution(intracellular P and extracellular P),and extracellular secretions(including EPS and siderophores)of microalgae were explored.The results showed that Fe^(2+)at 1.00 mg·L^(-1)concentration was conducive to the growth of M.aeruginosa,and at 0.05 mg·L^(-1)was beneficial to the growth of Scenedesmus sp.The Fe^(2+)concentration was positively correlated with the concentration of intracellular P and iron-bound P in M.aeruginosa,but negatively correlated with the extracellular P concentration.One day after Fe^(2+)addition,Fe^(2+)concentration was positively correlated with extracellular EPS proteins but negatively correlated with EPS polysaccharides.On the 14th day in Fe^(2+)treatment at 1.50 mg·L^(-1)concentration,the EPS protein concentrations of M.aeruginosa and Scenedesmus sp.were the highest,21.12 mg·L^(-1)and 19.19 mg·L^(-1),respectively.The results indicated that when at the low Fe^(2+)concentration conditions,the two microalgae could immediately secrete more siderophores to absorb iron and absorb extracellular P by secreting extracellular EPS polysaccharide.When at high Fe^(2+)concentration,it was beneficial to the yield of chlorophyll a and the accumulation of iron-bound P.The efficiency of M.aeruginosa in converting extracellular P to intracellular P was higher than that of Scenedesmus sp.,mainly existed as iron-bound P,which reduced the total P accumulation in algal cells.This study can provide theoretical guidance for blocking the supply cycle of e

关 键 词：二价铁 铜绿微囊藻 栅藻 磷赋存 铁吸收 EPS 铁载体 

分 类 号：X171.5[环境科学与工程—环境科学]