![]() The physiological and taxonomic implications of these findings are discussed. Light quality does not affect the differential rate of chlorophyll synthesis. Facultative hetrotrophs able to adapt chromatically have a phycobiliprotein composition after dark growth which closely resembles that after growth in red light. Chromatic adaptation is defined as: the alteration by photosynthesizing organisms of the proportions of their photosynthetic pigments in response to the intensity and color of the available light, as shown by algae in the littoral zone, which change from green to red as the zone is descended. Chromatic adaptation transforms are used to predict corresponding colours viewed under a different adapting illuminant. ![]() Quantitative data on the cellular pigment contents, supplemented by measurements of the differential rates of pigment synthesis on representative strains, show that chromatic adaptation may involve a light-induced modulation either of phycoerythrin synthesis alone (7 strains) or of both phycoerythrin and phycocyanin synthesis (25 strains). ![]() In the remaining strains, the cellular ratio of phycoerythrin to phycocyanin was much higher after growth in green than in red light. Supersaturated greens seen after long-wavelength adaptation depend upon contrast from the continuing afterdischarge of bleached red receptors in the. Twelve strains did not adapt chromatically: the cells contained fixed proportions of phycoerythrin, phycocyanin, and allophycocyanin under the growth conditions used. 1) from other parts of the world indicate. However, the reference white point to which the HVS adapts was investigated further. There is little direct evidence that this chromatic adaptation in fact occurs, and reports (for example ref. Cellular pigment compositions were determined after photoautotrophic growth with low light fluxes (7.0 X 10(2) ergs/cm2 per s) of green, red, and white light, and in the case of facultative heterotrophs, after dark growth at the expense of sugars. Chromatic adaptation modeling used in this model essentially consists of two stages, similar to the von Kries adaptation model 1) transformation from tristimulus values to HVS’s cone signals, and 2) compensation for chromatic adaptation. Forty-four axenic strains of cyanobacteria that synthesize phycoerythrin were screened to ascertain the effect of light quality on pigment synthesis.
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