Welcome to The Sound of Science from WNIJ and NIU STEAM. It’s a weekly series explaining important STEM concepts. Today’s hosts are Jeremy Benson and Newt Likier.
We have a question here from Ruth, who asks “What makes flowers different colors?”
There are two great ways to look at answering this question—genetics and light.
Let’s start off really simple with genetics. Like people, flowers have a DNA instructional manual for how to grow, what cells should be doing, and so much more. Some of those instructions lead to pigmentation, or the coloration of the flower’s petals. In many flowers, there are two types of pigmentation which produce shades of red and shades of blue.
There isn’t a red gene or a blue gene in flowers, though. Instead, a flower’s DNA contains instructions for chemical reactions, and many chemical reactions work together to create pigmentation. But there’s got to be a good reason for these reactions to occur, otherwise it’s just a waste of a flower’s precious resources.
That reason relates to the second part of our answer. People and creatures that see color usually have a series of rods and cones as part of their optics that react to specific wavelengths of light, which in turn tells the brain what colors they’re seeing.
In nature, these colors are very important. Bright colors can signal danger. In flowers, colors are an important signal for pollinators, like bees and birds. In fact, many bees and birds see a wider spectrum of light than people can, so some flowers have evolved to have infrared markings that are visible to them but not to us.
Both parts of this answer work together throughout a flower’s lifespan. A flower isn’t always ready to reproduce. Its DNA controls the intensity and hue of its pigments to communicate when it’s just right for a bumblebee to come on by and gather pollen. And because humans don’t usually participate, it isn’t necessary for us to see all those messages, resulting in flowers using patterns and colors on the visible light spectrum beyond our comprehension.
This has been the Sound of Science on WNIJ. Where you learn something new every day.
