Plant Coloration

The coloration of plants is determined by the presence of various pigments in the plant organs. The most common color, green, is due to the presence of chlorophyll, which plays a role along with a number of enzymes in photosynthesis. The yellow, red, blue, and other colors of flowers and fruits are determined by anthocyanins, which are dissolved in the cell sap, and by carotenoids, which are concentrated in plastids known as chromoplasts. The bright colors attract insects to pollinate the flowers and birds to disperse the fruits and seeds.

The varied coloration of algae is a result of adaptation to life at differing depths with varying light conditions. Green and blue-green algae are found in surface waters or in shallow bodies of water. Their green or blue coloration is due to the presence of the pigments chlorophyll and phycocyanin. Algae that live at greater depths usually are red or brown in color because of the presence of phycoerythrin (in red algae), fucoxanthin (in brown algae), or similar pigments. The coloration of certain fungi is determined by such pigments as riboflavin and chrysogenine. Coloration may be absent in most bacteria and fungi, as well as in a few higher plants (albinos or parasitic plants such as broom-rape and dodder).