Pigments accessory, in photosynthesis

Carotenes are essential accessory pigments in photosynthesis, but their exact role is not known. In in vitro experiments, carotenoids do not fluoresce, but they are able to sensitize the fluorescence of chlorophyll in green plants (Britton, 1983). 

Only two functions of carotenoids have been clearly documented. They have been shown to act as accessory pigments in photosynthesis and to function in photoprotection. A number of other possible functions have been proposed, however, and these are included in the discussion below. Certain metabolites of carotenoids also have important functions, particularly vitamin A and trisporic acids found in Mucorales. The functions of carotenoids have been reviewed (Krinsky, 1971 Burnett, 1976). 

Accessory pigments in photosynthesis ( ) Phycoerythrin Phycocyania Red and blue-green algae Red and blue-green algae Tetrapyrrole related to proto-porphin (7) Tetrapyrrole 290.000 275.000 (83,119) (129b)... 

Carotenoids Organic molecules that function as accessory pigments in phytoplankton photosynthesis. 

The carotenoids that serve as accessory pigments for photosynthesis absorb strongly in the blue region (425-490 nm Table 4-1) and moderately in the green region (490-560 nm), usually having triple-banded spectra from 400 to 550 nm. For P-carotene in hexane, the three bands are centered at... 

Phycocyanin and phycoerythrin, biliproteins of blue-green and red algae functioning as accessory pigments of photosynthesis, are easily obtained in large amounts and therefore have extensively been used as model compounds for phytochrome. 

Phycoerythrin and chlorophyll C2 are the accessory pigments for photosynthesis in the Cryptophycea (Lichtle et dt, 1980). 

Figure 5-15. Schematic model for a series representation of the two photosystems of photosynthesis, indicating the stoichiometry of various factors involved in the reduction of C02 to a carbohydrate ( CH20)). Some of the photons (hv) are captured by the accessory pigments and Chi a in the light-harvesting antennae these excitations are then fed into the two photosystems, but primarily to Photosystem II.

---