Changes in structure of isolated chloroplasts of Codium fragile and Caulerpa filiformis in response to osmotic shock and detergent treatment

• Published in: Protoplasma 1984-01, Vol.120 (3), p.155-164
• Main Authors: Grant, B.R, Borowitzka, M.A
• Format: Article
• Language: English
• Subjects: Algae; Biological and medical sciences; Caulerpa filiformis; cell membranes; Cell physiology; Cells, cell elements: structure and function; chloroplasts; Codium fragile; detergents; Fundamental and applied biological sciences. Psychology; Marine; osmotic shock; photosynthesis; Plant physiology and development; ultrastructure
• ISSN: 0033-183X; 1615-6102
• DOI: 10.1007/BF01282596

The ultrastructure of chloroplasts from two genera of coenocytic green algae, Codium and Caulerpa , were examined after suspension in hypotomic solution and in detergent at various concentrations. The capacity of the suspensions to carry out CO sub(2)-dependent and ferricyanide-dependent O sub(2) evolution was measured under the same conditions of osmotic strength and detergent concentration. The results show that exposure to hypotonic solutions and to detergent results in less damage to these chloroplasts than it would to those of higher plants. It is proposed that the basis of this unusual resistance is not due to the properties of the chloroplast membranes but to the presence of material which coats the organelles during isolation. This material is likely to be identical with the sulphated xylo-mannogalactan isolated from the vacuole contents of these algae and which has the visco-elastic properties essential to allow the organelles to resist disruption by osmotic forces and disintegration by detergents.