Photosynthetic pigments
During the process of photosynthesis, light energy is converted into the chemical energy. Light energy is captured by the photosynthetic pigments. Photosynthetic organisms have a variety of light absorbing pigments, therefore, they can absorb a wide range of wavelength. Most of the photosynthetic pigments absorb only specific wavelength of visible light, while reflecting others.
Three major classes of photosynthetic pigments, their appearance and absorption wavelength is listed in the below table.
| Pigments | Appearance | Absorption |
| Chlorophyll | Green | blue and orange-red |
| Carotenoids | Red/Orange/Yellow | blue-green and violet |
| Phycobilins | Bluish or Reddish | Green to red |
The absorption wavelength and appearance of a photosynthetic pigment can be easily understood with the help of
color wheel. In color wheel of split spectrum of visible light, a photosynthetic pigment appear just opposite to the color which it absorbs maximum.
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VIBGYOR color wheel showing opposite color of absorption and appearance
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For example: a pigment which absorbs maximum in the region of red appears green and so on.
Distribution of photosynthetic pigments
| Photosynthetic pigments | Distribution |
| Chlorophyll a | All photosynthetic plants, except bacteria
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| Chlorophyll b | Higher plants and green algae |
| Chlorophyll c | Brown algae and Diatoms |
| Chlorophyll d | Some red algae |
| Chlorophyll f | Stromatolites |
| Bacteriochlorophyll a | Purple and green bacteria |
| Bacteriochlorophyll b | Purple bacteria |
| Chlorobium chl a | Green sulfur bacteria |
| Chlorobium chl b | Green sulfur bacteria |
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| Carotenes | Algae and Higher plants |
| Xanthophylls | Algae and Higher plants |
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| Phycocyanins | Blue Green algae and Red algae |
| Phycoerythrins | Blue Green algae and Red algae |
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