Cell Wall Composition of the Conchocelis Phases of Bangia atropurpurea and Porphyra leucosticta (Rhodophyta)

Mechanically isolated cell walls were prepared from the conchocelis phases of Bangia atropurpurea (Roth) C. Ag. and Porphyra leucosticta Thur. Electron microscopic observations of cell wall preparations revealed them to be morphologically similar to walls of whole thalli and free from protoplasmic contamination. Chemical analyses of isolated walls demonstrated several similarities in wall composition between the conchocelis of the two species. Walls contained over 40% polysaccharide with the predominant polymer a galactan. Xylose was found associated with this hot water-soluble galactan. Cellulose comprised 3.8% and 5.5% of B. atropurpurea and P. leucosticta wall weight, respectively. A small amount of mannan was detected and walls contained over 22% lipid and 7.0% protein. Cell wall hydrolysates contained at least 14 amino acids of which aspartic acid, alanine, glycine and arginine were the most prevalent. The cell wall composition of the conchocelis of B. atropurpurea and P. leucosticta is distinct from that previously reported for the generic phases of Bangia and Porphyra.