As we are approaching fall, with the gentle breeze, warm drinks, fuzzy socks, sweet scents, fun activities, autumn decorations, and, of course, the beautiful display of bright colors, many of us go out of our way to step on the fallen, crunchy leaves. But why do leaves turn old and crispy? Why do the leaves change colors? What is the science behind the beautiful and unique fashion show of fall colors?
The magic behind the scenes can be attributed to one ingredient; pigments. Chlorophyll, the green pigment, absorbs sunlight in order to provide energy for the process of photosynthesis. This is the most well known pigment, as everyone sees it for three out of the four seasons. However, in the fall, when the sun shines less due to shorter days and longer nights, the leaves don’t have as much sunlight to absorb. Therefore, chlorophyll doesn’t play as large of a role in the colder, darker seasons that it does in the warm, sunny seasons. While chlorophyll takes a bow and exits the fashion show, other pigments step up to the stage and show off their colors. The following pigments are responsible for their specific colors and the roles they play in helping the plant.
Yellow Color: Xanthophylls, aids chlorophyll in light-harvesting
Oranger Color: Carotenoids, protects chlorophyll from sun damage
Red Color: Anthocyanins, filter out yellow-green light and diminish oxidative levels
Overall, the fabulous fashion show that occurs every fall can be attributed to the simple magic of pigment.