A Histochemical Study of Bud Initiation in the Brown Alga Sphacelaria Furcigera*

Abstract

SUMMARYPrevious ultrastructural studies of Sphacelaria furcigera have revealed the existence of distinct ' morphological' layers within the outer longitudinal cell walls. Bud initiation and development from an axial mother cell involve a change in the layering pattem. The histochemical evidence suggests that the cell wall is composed primarily of alternating layers of sulphated polysaccharides (fucans) and acidic polysaccharides (alignates). Structural integrity of the developing bud cell wall appears to be maintained by a thickened inner alginate layer. The abundance of protein sublayers within the bud cell wall may reflect the presence of enzymes which participate in cell wall loosening and/or synthesis. In addition, a number of the histochemical techniques employed in tbis study were also applied to the brown alga Fucus distichus for comparative purposes. Tbe results emphasize the need for caution when interpreting histocbemical data. Toluidine blue O metacbromasia and tbe periodic acid-Scbiff's reaction are evaluated critically and suggestions are given for improving histocbemical interpretations.

Immunogold-labeling analysis of alginate distributions in the cell walls of chromophyte algae

“…The existence of alginates in brown algal cell walls has been confirmed by differential, histochemical staining and indicated to be localized in particular layers of the cell walls (McCully 1966;Evans and Holligan 1972;Burns et al 1982). Alginic acid is composed of three different oligosaccharides, mannuronic acid (M) blocks, guluronic acid (G) blocks, and blocks with alternating mannuronic and guluronic (MG) units (Haug et al 1974).…”

Changes in Cell Wall Structure During Rhizoid Formation of Silvetia babingtonii (Fucales, Phaeophyceae) Zygotes

“…In Sphacelaria furcigera , bud (branch) formation was observed (Burns et al. 1982a,b). The axial cell wall is composed of four layers (CW1–CW4), but the initial bud region is covered by two newly synthesized layers (CWO and CWI).…”

“…Burns et al. (1982a) suggested that alginates are abundant in CW2, CW4, and CWI, while sulfated fucans were prominent in CW1, CW3, and CWO. Cell wall structure on the rhizoid tip in fucoid zygotes has been observed (Novotny and Forman 1975, Callow et al.…”

“…At the light microscopic level, metachromatic analysis using toluidine blue and periodic acid‐Schiff (PAS) was performed to detect alginate and sulfated fucan (Novotny and Forman 1975, Burns et al. 1982a). Recently, monoclonal antibodies that recognize different structures of alginate and sulfated fucan were produced, and immunofluorescence data on the localization of these epitopes in some brown algal species were collected (Torode et al.…”