Piles of leaves and hiding—they just go together. Ticks and other creepy crawlies take shelter under these natural golden hideaways. Forest creatures flit and scurry beneath the cover of this verdant camouflage. Hunters and trackers disguise their traps and stands under leaves. Even our first parents, Adam and Eve, swiped a few fig leaves to cover themselves after they sinned against their Creator.
With all this foliage fakery, should we be surprised that leaves even hide their own colors? It’s true. Their real hues don’t always shine through.
Now, you might look out your window at an autumn explosion of yellows and golds, reds and purples, and wonder how leaves could possibly keep their colors under wraps. After all, this brilliant fall festival would be tough to mute, right?
Let’s just put it this way: green has a way of hogging the spotlight for most of the year.
You see, during spring and summer, leaves focus on the green side of the work God designed them to do. These thin, energy-producing wonders take in carbon dioxide and sunshine and produce sugars and oxygen. (The plants get sugar, and we get air to breathe—pretty handy, really.) But this energy production, called photosynthesis, wouldn’t happen without tiny green biomolecules called chlorophylls.
Here’s how the hide-all-colors-but-green works. When sunlight strikes the chlorophyll molecules, they start vibrating and send out charged electrons that run the sugar-making factory. Chlorophyll is picky about which colors it uses, however. Sure, sunlight seems pretty yellow to us, but it actually comes to earth with a full spectrum of colors. (You can see them all when a rainbow forms.) Chlorophyll ushers the red and blue parts of light right into making energy, but the green part bounces off. That scattered green finds its way to your eyes, and suddenly leaves look completely green to us.
So, what does this have to do with reds and yellows lurking beneath the surface? Well, you could say that chlorophyll comes on pretty strong. In fact, all that green bouncing around keeps you from seeing the other colors. (Try the experiment to “unhide” these stunning hues.)
When autumn comes and the days grow shorter, trees shut down their energy factories. They stop making green chlorophyll, which quickly fades away—and other colors get their chance to shine through. The two other main pigments in most leaves—xanthophylls (yellow pigments) and carotenes (orange ones)—take longer to break down than the more dominant chlorophyll. That’s why those leaves you rake up are so festive (even if they don’t feel that way when your yard is covered).
What do these other pigments do? Well, these “crowded out” pigments play a part in photosynthesis, too. They gather additional wavelengths of sunlight, which they pass along to the chlorophyll.
They also work behind the scenes to help protect leaves. The yellow, for example, seems to protect the leaves from the high-intensity rays of the sun. When chlorophyll gets too excited and charged up, the yellow may slow things down a bit. Meanwhile, the orange limits the destructive effects of oxygen during photosynthesis.
By the way, you’d be right if you thought the name carotene comes from “carrot” (the Latin root, anyway). This orange, vitamin-rich hydrocarbon gives the distinctive coloration of carrots, sweet potatoes, and, in a roundabout way, the yellow color in your butter. It also makes orange leaves pop.
What about red leaves? The red pigment comes from the late-to-the-game anthocyanins, and only some leaves get it. You’ll find this same red pigment in apples and strawberries.
Sugar maple leaves are probably the most well known for their royal reds. They produce anthocyanins during the short autumn days. Many reasons have been suggested for this latecomer. Along with added protection against sunlight, the most widely accepted belief is that the red pigment helps trees recover the last few nutrients from their leaves before winter.
That brings us to an important question. Why would God hide such beautiful colors in leaves? Why not just let them be red or yellow all year?
Our wise Creator gave plants a very efficient system for making energy. Green leaves, which are a darker color, do the best job gathering in the sunlight. (That’s why dark clothes get warm quickly.) But when you mix all these colors together in one leaf, they work together to absorb even more light from all over the spectrum.
So, leaves may hide their true colors, but they’re all there. And in the fall they publicize how creative their Creator is.
See for Yourself . . .
You can uncover the hidden colors of leaves right in your kitchen. (Make sure you have a parent’s permission before you start.)
A variety of green leaves from several different types of trees (try to find several of each type if possible—such as three red maple leaves, four oak leaves, etc.)
Small drinking glasses (one for each type of leaf)
Bowls (one for each glass)
Isopropyl alcohol (you may know it as clear rubbing alcohol)
Filter paper (you can use coffee filters)
Pencils or pens (one for each glass)
Tape or clothes pins
- Tear your leaves into small pieces and put them in separate glasses based on type (e.g., all the red maple in one glass, and all the green oak in another glass).
- Pour in just enough rubbing alcohol to cover the leaf pieces.
- Cover the glasses with plastic wrap to keep the alcohol from evaporating.
- Have an adult carefully pour hot water into each bowl.
- Place each of the glasses with the leaf pieces in separate bowls and let them sit for about 30 minutes. The alcohol should take on the green color of the leaves.
- While you wait, cut the filter paper or coffee filters into half-inch strips, which you will use to separate the different colors. (Longer strips are better because you may need to adjust the length in a bit.)
- Tape one strip to the middle of each pencil so that it can hang down from the pencil.
- Place the pencil across the mouth of each glass and let the strip hang down to just barely touch the alcohol mixture. (You may need to trim the strips to get this to work.)
- Play a game or do homework for about an hour.
- Observe what colors you see on each strip. Which leaf had the most color? Which color is most brilliant (and likely to be the most intensely colorful in the fall)?