THE LIFE-CYCLE OF EMILIANIA-HUXLEYI - A BRIEF REVIEW AND A STUDY OF RELATIVE PLOIDY LEVELS ANALYZED BY FLOW-CYTOMETRY

Emiliania huxleyi exists in several principal forms including the fami liar coccolith-tearing C-cell, non-motile naked N-cells, and scale-bea ring swarmers (S-cells), but the relationships between these cells are unclear. Flow cytometric analyses have been undertaken on whole cells using fluorochrome staining of the DNA in order to determine the rela tive DNA content and the relative GC content of the S- and C-cells of selected clones. Results showed that the DNA complement of the S-cells was half that of the C-cells and the two cell types are, therefore, h aploid and diploid relative to each other, The S-cells may, therefore, represent a gametic stage, though processes such as sexual fusion and meiosis have not been observed.