How Do Flowers Get Their Pigments?

Flowers exhibit a startling variety of colors.

Flowers contain pigments that absorb specific wavelengths of light and reflect others. The human brain interprets as colors the wavelengths as registered by photoreceptors.

Features

Anthocyanins are common pigment molecules found in many flowers. They are synthesized in the cells of the developing flower and stored in the vacuole, a structure inside the cell. The structure of the molecule endows it with the properties that give it what humans perceive as color.

Function

Pigment molecules are synthesized through a complex series of reactions catalyzed by enzymes. The genes for these enzymes can be "switched on" or "switched off" by transcription factors, gene regulatory proteins that are activated at a specific point during cell differentiation and flower formation.

Fun Fact

Some flowers vary color in response to soil pH. For example, hydrangeas planted in acidic soils often exhibit a different color from flowers planted in alkaline soils.

References

• Plant Cell: ANTHOCYANIN1 of Petunia Controls Pigment Synthesis, Vacuolar pH and Seed Coat Development
• University of Vermont Extension: Color in Flowers OH 24
• Purdue University: Metabolic Plant Physiology, Anthocyanins
• "Genetics: A Conceptual Approach"; Benjamin A. Pierce; 2006

Resources

• USDA: Cracking Nature's Color-Code for Flowers