A histochemical study of Corallina officinalis (Rhodophyta, Corallinaceae)

Abstract

Abstract A branch of Corallina officinalis L. consists of (1) an apical meristem of intensely active cells, (2) intergenicula of small, calcite encased, vegetative cells, and (3) uncalcified genicula made up of long cells. Histochemical analyses were carried out to examine developmental and structural changes in apical, intergenicular and genicular tissues with regard to the occurrence of pectins, starch, cellulose, protein, CaCO3 and nucleic acids. Vegetative cell walls consist of an inner cellulosic layer and a thicker middle layer composed of a pectin-like substance and CaCO3. The end walls of intergenicular cells are unusually rich in cellulose. A stratified cuticle covering all calcified surfaces is secreted by underlying cells. It is pectin-like and protein-free and made up of highly compressed layers over epithallial cells and more loosely compacted layers over branch apices. Starch deposition progresses centripetally in the intergenicular medulla. The uncalcified parts of genicular cells produce c...