Airdate: Oct 11, 2002
Scientist: Nina Bassuk
Fall Leaves: Family Tree
Genetic coding of individual leaves make for the resplendent beauty of Fall foliage.
ambience: sound of walking, the crunching of leaves
The nuclear family is not so different from the family of leaves on a tree. Just like children from the same parents are unique individuals, each leaf of a tree has its own particular genetic code. I’m Jim Metzner, and this is the Pulse of the Planet. The best time to tell the leaves of different species of trees apart is during the Fall, when the most spectacular leaf color prevails.
"Every plant has a signature fall color that's part of their identification pattern. The Beech have a beautiful yellow color, a kind of golden yellow color quite late in the autumn season. Of course, Sugar Maples are the real winners in the Northeast in terms of their gorgeous orange-red-yellow glowing color. The Cherries have a kind of golden-reddish tinge and all together they just make a great cacophony of color."
Nina Bassuk is Director of the Urban Horticultural Institute at Cornell University.
"In each leaf, according to its own genetic code, there’s a group of pigments that have various metabolic functions. Of course chlorophyll is the green one which we most often see, and then as that breaks down in fall we get to peer at the other colors. Some people might wonder when they see three Maples, why some of them have different colors than the others -- they’re all Maples. But in fact different species of Maple have different signature colors and they change color at different times within the fall season. For instance, Red Maple, which is a very common species we see here -- some individuals might have yellow leaves and some might have very brilliant red leaves. The same as if you have children of a family and one might have dark hair and another blond hair and so on. So there are individual differences even within a species."
So although two leaves may be from the same family, no two leaves are alike.
Pulse of the Planet is presented by DuPont, bringing you miracles of science for 200 years, with additional support provided by the National Science Foundation. I’m Jim Metzner.