中国淡水绿藻纲新记录属——麦可属(Mychonastes)

摘要

Morphology,ultrastructure,and 18S rRNA gene sequences of two strains of eukaryotic picoplankton isolated from Lake Dianchi,China,were analysed.Results showed that cellular shape,structure and autosporulation of two strains were similar to characteristics of the genus Mychonastes Simpson & Van Valkenburg.The cell wall was consisted of double layers.The outer layer had a network of ribs on its surface and a trilaminar sheath,which appeared as a dark-light-dark triple layer.Cells had a minimal set of organelles,typical for small coccoid green algae,a single nucleus,one mitochondrion,one chloroplast without pyrenoid.Chloroplast was parietal,cup-shaped and occupied most of the cell volume.The phylogenetic tree based on 18S rRNA gene sequence data showed that isolated strains belonged to the genus Mychonastes,which belonged to the Chlorophyceae (Chlorophyta).Mychonastes was a firstly recorded genus of eukaryotic freshwater picoalgae in China.%从我国滇池分离、培养获得2株超微真核藻,对其进行形态学、细胞超微结构和18S rRNA基因序列分析.结果表明:藻株在细胞形态、结构和繁殖方式具麦可属(Mychonastes Simpson&Van Valkenburg)特征,细胞壁2层,外层细胞壁表面具不规则肋网和典型的暗-明-暗结构；具备一套简单的细胞器,包括细胞核、不具蛋白核的叶绿体和线粒体各1个,叶绿体周生、杯状,占据细胞大部分体积；以似亲孢子方式繁殖.结合18S rRNA序列分析,将其归为麦可属,属于绿藻纲、绿藻门,是该属在我国淡水湖泊的首次描述.