Why Do Flowers Have Different Colours?

Different flowers are different colours be-cause their petal cells contain specific "chem-ical dyes", namely pigment. Under certain conditions the pigments change colour. Take anthocyanidin for instance, it can become red, blue and purple. When petals contain enough carotene, they will look yellow, orange and dark brown. Green petals mainly contain chlorophyll. Petals of white flowers have no pig-ments, but are full of air bubbles. If you flatten the bubbles by squeezing the petals, they will become transparent.