群体细胞间空隙在微囊藻水华形成过程中的浮力调节作用  

Role of Conony Intercellular Space in the Cyanobacteria Bloom-Forming

作　　者：张永生[1] 李海英[2,3] 孔繁翔[1] 于洋[1] 张民[1] 

机构地区：[1]中国科学院南京地理与湖泊研究所湖泊与环境国家重点实验室,南京210008 [2]国家水电可持续发展研究中心,北京100038 [3]中国水利水电科学研究院,北京100038

出　　处：《环境科学》2011年第6期1602-1607,共6页Environmental Science

基　　金：国家重点基础研究发展规划(973)项目(2008CB418000)

摘　　要：伪空胞一直被认为是蓝藻水华形成过程中的主要浮力提供者,但是否是唯一的浮力提供者还不清楚.本研究利用室内蓝藻水华形成模拟实验和野外验相结合的方法,从生理生态学角度探讨细胞间空隙对蓝藻水华形成的影响.室内蓝藻水华形成模拟实验表明,蓝藻在上浮过程中以单细胞形态存在,但在水柱培养器取样口6开始形成小群体;通过对细胞镇重物(胞外多糖、细胞干重和蛋白质等)的含量的分析表明,胞外多糖在蓝藻上浮过程中,变化率最大,含量在水柱培养器取样口6处达到最大值,在3次实验过程中,胞外多糖的量分别为:3.02、10.38和15.73 pg/cell.野外蓝藻群体显示群体内部具有大量的细胞间空隙;将野外蓝藻群体分别经1.0 MPa压力和超声波破碎仪40 Hz处理1min,结果发现蓝藻在1.0 MPa压力下,群体内部不存在细胞间空隙,并且伪空胞破裂,蓝藻不能上浮,但在超声波处理下,蓝藻群体被打散成单细胞悬浮在水体中,但伪空胞是完好无损.实验结果表明,蓝藻利用胞外多糖将蓝藻单细胞聚集成群体,形成细胞间空隙,细胞间空隙产生的浮力是蓝藻水华形成的主要因素之一.Gas vesicle is considered a major factor providing buoyancy for cyanobacteria ascending.However,whether other buoyancy contributing factors exist is still unclear.In this study,we combined indoor bloom simulation and field experiments to explore the impact of intercellular spaces on algal bloom formation.Indoor bloom simulation studies indicated that cyanobacteria exist as single cells when floating,but form small colonies at port 6.Cell ballast analysis [exopolysaccharide（EPS）,cellular dry weight,protein,etc.] showed that EPS exhibits the most rapid change rate and the maximum level of cyanobacteria rises at port 6,which were 3.02,10.38 and 15.73 pg/cell in three tests respectively.Field algae investigation revealed abundant intercellular spaces within algal colonies.When the field colonies were treated with 1.0 MPa pressure and ultrasonic processor at 40 Hz for 1 min,respectively,intercellular spaces disappeared and gas vesicles collapsed under 1.0 MPa pressure,causing increasing cyanobacteria failure.Under sonication,algal colonies were broken down into single cells that became suspended in water,but gas vesicles remained intact.These results suggested that single algal cells aggregate into colonies through EPS and form intercellular spaces to provide buoyancy,which is one of the major factors for bloom formation.

关 键 词：蓝藻 细胞间空隙 浮力调节 水华形成 浮力提供因子 

分 类 号：X52[环境科学与工程—环境工程]