Understanding the Role of Pigments in Flowers

MARIA GABRIELA LAGORIO

Flowers: Morphology, Evolutionary Diversification and Implications for the Environment

Nova Science Publishers

Lugar: New York; Año: 2013; p. 55 - 73

Betalains, anthocyanins, carotenoids and chlorophylls, are the main pigments present in flowers. Anthocyanins and betalains are mutually exclusive and they are never found together in a plant. The main function of the pigments in flowers is giving them colour and thus to provide an attraction signal to pollinators. The hue of flowers, however, not only depends on the nature of their pigments but it is also influenced by the presence of co-pigments, the cellular pH and the incorporation of metal ions. Other factors like light conditions and temperature also affects the spectral distribution of the light reflected by the pigments and as consequence the flower color. Several auhors have also observed fluorescence emission from betalains in flowers. The reflected light and the light emitted as fluorescence by flowers pigments may be analysed in terms of their relevance in biosignalling towards pollinators. For this survey, not only the spectral distribution of the light given off from the flowers, but also the sunlight spectrum and the sensitive response of pollinators photoreceptors should be considered. Some flowers pigments show also a defensive function acting as toxics to predator insects. It was found that carotenoids are related to flowers flavor as they act as precursors of chemicals which are responsible for the fragrance of some flowers