一株耐受高浓度硫酸镁单细胞绿藻的分类学鉴定及单盐胁迫对其生长的影响

TAXONOMIC STUDY OF A UNICELLULAR GREEN ALGA SURVIVING IN HIGH CONCENTRATION MAGNESIUM SULFATE SOLUTION, AND ITS TOLERANCE AGAINST PURE SALT STRESS

在75g/L浓度的硫酸镁溶液中发现了一株生长良好的单细胞绿藻。为了解这株特殊微藻的系统进化学分类地位和潜在利用价值,本文结合了分子系统学方法和形态特征,并测定其不同盐环境下的光合效率,以探讨其对于硫酸镁盐的耐受机理。结果表明,基于该藻株18S及ITS r DNA序列构建的系统进化树确认其隶属于胶球藻属。该株藻细胞为椭圆形、具有较小的长宽比、色素体多为分叶的2瓣和无明显胶被等特征与胶球形胶球藻较接近,系统发育分析显示其与伪胶球藻株系和与地衣Peltigerales共生株系亲缘关系较近。对该藻不同培养条件下的耐受特征做出初步探索,结果表明其对硫酸镁有着独特的单盐抗性,并可以耐受蒸馏水环境。这些特性表明该藻株有良好的抗杂藻污染特性,具有潜在应用前景。

A unicellular green alga was isolated from 75g/L magnesium sulfate and cultured successfully. Molecular and morphology analyses were made to infer its phylogenetic position and another preliminary research were conducted to determine its ability against pure magnesium sulfate solution stress. The morphology of the strain was observed with light microscope and transmission electron microscope. Phylogenetic analyses based on 18S and ITS rDNA sequences demonstrated that this strain is an uncertain species of Coccomyxa and clearly related to a Pesudococcomyxa clade and a lichenized Coccomyxa clade, forming a strong lineage within the Coccomyxa complex. In addition, morphological observation showed that the alga is similar to C. gloeobotrydiformis, and different from other species of the genus showing no mucilage and having only two or bilobate chloroplasts in matured cell. The physiological study on different cultural conditions revealed that it has a unique ability against single magnesium sulfate stress and tolerance against distilled water.