BETAINE LIPID-CONTENT AND SPECIES DELIMITATION IN ECTOCARPUS, FELDMANNIA AND HINCKSIA (ECTOCARPALES, PHAEOPHYCEAE)

The lipid composition of 140 clonal isolates of brown algae, covering 16 species of the genera Ectocarpus, Feldmannia and Hincksia, was anal ysed. All taxa contained the glycolipids monogalactosyldiacylglycerol, digalactosyldiacylglycerol and sulphoquinovosyldiacylglycerol, and th e phospholipids phosphatidylcholine, phosphatidylethanolamine, phospha tidylglycerol, phosphatidylinositol and an unidentified PX. Presence o f the betaine lipid diacylglycerylhydroxymethyltrimethyl-beta-alanine (DGTA) was strongly correlated with certain species in the genera Hinc ksia and Ectocarpus. While seven species of Hincksia contained DGTA, t his lipid was absent in H. granulosa and in an unidentified Hincksia s pecies. Due to heteromorphy of generations, species assignments in the genus Ectocarpus were made only for isolates for which the complete l ife history was known. We found that E. fasciculatus contains DGTA, wh ile this lipid is absent in E. siliculosus. A collection of 40 non-sex ual Ectocarpus strains included representatives with and without DGTA. The value of DGTA as a taxonomic marker in Ectocarpus and Hincksia is discussed.