GELIDIUM-SESQUIPEDALE (GELIDIALES, RHODOPHYTA) .2. AN ULTRASTRUCTURALAND MORPHOLOGICAL-STUDY

The ultrastructure of the red alga Gelidium sesquipedale has been inve stigated by optical, scanning and transmission electron microscopy, cr oss polarization magic angle spinning carbon-13 N. M. R. spectroscopy together with X-ray and electron diffraction analysis. After agar extr action, the thalli could be fragmented into their elementary cell comp onents namely rhizines, medullary and cortical cells. Analysis of thes e cells after enzymatic and acid hydrolysis showed that a cellulosic m icrofibrillar network was one of the main components of their cell wal ls. A cuticle consisting of a proteinaceous membrane encrusted with co rtical cells was also isolated and characterized when the thalli were exhaustively treated with cellulase.