October 4, 2012
One of the greatest treats Michigan offers is the annual fall color show, and I find it’s nice to have a little deeper appreciation about what’s going on inside sugar maples and other trees whose leaves change color in the fall. The Science of Color in Autumn Leaves from the US Arboretum explains that:
During the growing season, chlorophyll is replaced constantly in the leaves. Chlorophyll breaks down with exposure to light in the same way that colored paper fades in sunlight. The leaves must manufacture new chlorophyll to replace chlorophyll that is lost in this way. In autumn, when the connection between the leaf and the rest of the plant begins to be blocked off, the production of chlorophyll slows and then stops. In a relatively short time period, the chlorophyll disappears completely.
This is when autumn colors are revealed. Chlorophyll normally masks the yellow pigments known as xanthophylls and the orange pigments called carotenoids — both then become visible when the green chlorophyll is gone. These colors are present in the leaf throughout the growing season. Red and purple pigments come from anthocyanins. In the fall anthocyanins are manufactured from the sugars that are trapped in the leaf. In most plants anthocyanins are typically not present during the growing season.
Set your background for fall with this photo or find lots more Fall wallpaper on Michigan in Pictures!