Surface ornamentation of Cyanophora paradoxa (Cyanophorales, Glaucophyta) cells as revealed by ultra-high resolution field emission scanning electron microscopy

Abstract

Cyanophora paradoxa is an enigmatic biflagellate that may represent the first photosynthetic eukaryote morphologically. This alga has been widely studied as a model organism of primitive phototrophs. However, surface ornamentations of the vegetative cells have not been examined using ultra-high resolution field emission (FE) scanning electron microscopy (SEM). In the present study, C. paradoxa NIES-547 vegetative cells were examined using FE-SEM and compared with the data using conventional SEM. Our FE-SEM images demonstrated that the cell surface was ornamented with angular fenestrations framed by ridges. In contrast, conventional SEM did not reveal similar surface ornamentation. Transmission electron microscopy showed the ridge was formed by the edges of overlapping or attaching outermost plate vesicles at the cell periphery. ©2014 The Japan Mendel Society.