Carotenoids of blue-green algae—11. carotenoids of chromatically-adapted cyanobacteria

Abstract

1. 1. The total carotenoid content and carotenoid composition of a Lyngbya-Plectonema-Phormidium (L.P.P.) sp., Fremyella diplosiphon and Tolypothrix tenuis grown in semicontinuous culture in white light or red light ( >590 nm ) are reported. 2. 2. Complementary chromatic adaptation of these cyanobacteria is manifested by changes in phycobiliprotein synthesis and also effected the carotenoid synthesis. 3. 3. The total carotenoid content of L.P.P. sp. nearly doubled with a selective increase in the concentrations of β,β-carotene and zeaxanthin when the cells were grown in red light compared with white light. 4. 4. F. diplosiphon showed a 45% and T. tenuis a 21% reduction in total carotenoids with no significant selective effect on individual carotenoids, including ketonic and glycosidic types, under the same illumination conditions. 5. 5. There is apparently a direct relationship between total carotenoid content and phycobilisome size for L.P.P. sp. and F. diplosiphon, which may be associated with the protective effect of carotenoids against photosensitized oxidation. 6. 6. The Kezar Lake strain of Aphanizomenon flos-aquae (white light only) differed in carotenoid composition with previous results.