CHLOROPLAST PIGMENT PATTERNS IN DINOFLAGELLATES1

SUMMARY The chlorophylls and carotenoids of 22 species of dinoflagellates were analysed by thin layer chromatography, using 2‐dimensional sucrose plates, and 1‐dimensional polyethylene plates for chlorophylls c1and c2. Peridinin was the major carotenoid in 19 of the species, while fucoxanthin was the major carotenoid in 3. In the peridinin‐containing species, 5 carotenoid fractions, constituting more than 95% of the total carotenoids, were always present. These were peridinin (± neo‐peridinin), averaging 64% of the total carotenoid, diadinoxanthin, dinoxanthin, β‐carotene and a polar, unidentified pink xanthophyll. Six other carotenoid fractions occurred in minor or trace quantities among the species, but were not identified. Two of these had, a wide distribution; the other 4 were restricted to one or 2 species. The chlorophyll content of the dinoflagellate cultures ranged from 1–141 μg chlorophyll a + c/106cells, a pattern which was broadly correlated with cell size. In the peridinin‐containing species the ratio of chlorophyll a to c on a molar basis was approximately 2 (range 1.60–4.39); in the fucoxanthin‐containing species this ratio was approximately 4 (range 2.65–5.73). Both chlorophylls c1and c2occurred in the fucoxanthin‐containing dinoflagellates, and only chlorophyll c2(one exception) occurred in the peridinin‐containing dinoflagellates. These patterns of chlorophyll c and major carotenoid correspond to patterns previously observed in the Pyrrhophyta and the Chrysophyta, suggesting different phylogenetic origins for the “dinoflagellate” chloroplasts.