TAXONOMIC STUDY OF A UNICELLULAR GREEN ALGA SURVIVING IN HIGH CONCENTRATION MAGNESIUM SULFATE SOLUTION, AND ITS TOLERANCE AGAINST PURE SALT STRESS
LIU Xu-Dong;LIU Guo-Xiang;HU Zheng-Yu;Institute of Hydrobiology, Chinese Academy of Sciences;University of Chinese Academy of Sciences;
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 18 S and ITS r DNA 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.