LOW MOLECULAR WEIGHT CARBOHYDRATE PATTERNS IN THE BANGIOPHYCEAE (RHODOPHYTA)

Abstract

The qualitative and quantitative occurrence of low molecular weight carbohydrates (LMWCs) in the Bangiophyceae is surveyed. Members of the orders Erythropeltidales ( Sahlingia and Erythrotrichia ), Compsopogonales ( Compsopogon ), and Bangiales ( Bangia and Porphyra ) all contain floridoside and, in some cases, D‐ and L‐isofloridoside, making the group chemotaxonomically the most homogeneous; L‐isofloridoside occurred only in the Bangiales. The Porphyridiales showed great variation in carbohydrate types: Chroodactylon contained only sorbitol, Porphyridium contained only floridoside, Dixoniella and Rhodella species exhibited only mannitol, and Rhodosorus showed digeneaside and sorbitol, whereas Stylonema contained floridoside, D‐isofloridoside, digeneaside, and sorbitol. The extensive variation in LMWC composition within and between the different orders suggests that the enzyme systems for each might have developed repeatedly in different Bangiophyceae and Florideophyceae. Nonetheless, a phylogenetic tree based on small‐subunit ribosomal RNA supports the LMWC patterns in the Bangiophyceae.