sound strange. Plants can see you. T ey know when you stand over them. T ey even know if you’re wearing blue or red. Plants don’t have eyes like we do, and they
don’t see in the same way that we do. Yet they have many ways to detect light. Seeing is just one way in which plants learn
about their world. Plants can feel and smell, too. You might think I’m joking. I’m not. I’m a scientist who studies plants. I’ve spent many years asking a key question
about plants. What do plants know? Other scientists have asked this question, too. We have all studied plants to try to find the answer. We have observed how plants grow and live.
T en we’ve shared our work with one another. We’ve learned many surprising things from our observations. I think the most surprising is that plants have senses.
A Sense of Sight I can tell you that plants can see. Yet it’s not
enough for a scientist like me to say that. It has to be tested and proven. Let me give you an example. A long time
ago, a scientist named Charles Darwin had an idea about plants. He observed that plants bend toward light as they grow. So Darwin came up with an explanation
for why plants bend toward light. He thought that plants could see light. Next, he had to figure out what part a plant uses to sense light. Aſt er all, plants don’t have eyes. He made a hypothesis, or guess, that the part was at the tip. Now he needed a method to prove his hypothesis.
20 NATIONAL GEOGRAPHIC EXPLORER
going to tell you something that might
The Experiment Darwin’s method was an experiment, or test.
He planted five seeds. T e seeds grew into tall shoots. Darwin let the first shoot grow normally. He made changes to all the others. He snipped off the tip of the second shoot. He covered the tip of the third shoot with a dark cap. He covered the tip of the fourth shoot with a glass cap. He covered the middle part of the fiſt h shoot. T en he waited. T ree of the shoots kept growing. T ey bent
toward light. T e shoot that was missing its tip didn’t. Neither did the shoot with the dark cap on its tip. From this experiment, Darwin was able to make a conclusion. He had proven that plants could sense light. He also proved that they used the tip to do this. Other scientists repeated his experiment
and got the same results. T ey tried new experiments and found that plants knew the diff erence between blue and red light. T ey bend toward blue light, but not toward red.
A Sense of Touch People touch plants all the time. We walk on
grass. We pluck flowers. We pick fruit. What if plants knew we were touching them? I’ve got news for you. T ey do. Plants can feel. T ey don’t feel pain. Yet they
can tell hot from cold. T ey know if the wind is blowing on them. T ey know if it’s raining. You’re wondering how we know this is
true. Observations, of course! To learn about a plant’s sense of touch, scientists studied many kinds of plants. One of those plants was the Venus flytrap.
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