Suntory Global Innovation Center

Mechanisms by which flower colors are determined

Plants contrive various ways to attract insects and birds that carry their pollens. The use of flower colors is one of these ways, and they have flowers of various colors that appeal to insects and birds. Representative flower color components include: 1) flavonoids, which produce many colors from yellow to blue (morning glory, carnation, geranium, etc.), 2) carotenoids, from yellow to orange (yellow chrysanthemum and rose, components of tomato and carrot, etc.), and 3) betalains, contained in some plants (four-o'clock, cactus, etc.) and mushrooms (see the figure below). Among them, Suntory has been conducting studies of flavonoids. Flavonoids include many compounds that are good for health. Anthocyanins in blueberries, which are considered to be good for eyes (red and blue pigments among flavonoids are called anthocyanins), and catechin belongs to the class of flavonoids.
Flavonoids are synthesized from phenylalanine (a kind of amino acid) with the work of many enzymes. Flower colors are determined depending on which enzymes work and how much they work. For example, if enzymes to produce blue pigments work, blue flowers bloom, and if enzymes to produce red pigments work, red flowers bloom.