Avery Elizabeth Hurt writes:

It’s a pleasant summer morning. Across a field, a line of poplar trees sways in the breeze. Insects buzz and flit among the branches. Everything seems calm and peaceful.

But don’t be fooled. These trees are actually under attack as hungry insects chomp on their leaves.

The trees can’t hide, and they can’t run away. But they aren’t helpless: They have ways to fight back — and even aid each other. As soon as an insect starts gnawing on a leaf, the tree mounts defenses. It also quickly messages its neighbors: “We’re under attack! Get your defenses ready!” It might even call on other insects for help.

All of this happens in ways we don’t see. But scientists are learning that plants can do many things we associate with thinking. Plants communicate with each other. They can learn. They form memories. They can even recognize their relatives. And they do all this without a brain.

Could these abilities mean plants are intelligent? We may never fully know. As Simon Gilroy puts it, “It’s very difficult to think like a vegetable.” Still, researchers are working to get to the root of what’s going on when plants act in ways we once thought only animals could.

“When you look at a tree,” says Gilroy, “it looks like it’s doing absolutely nothing.” Gilroy is a botanist at the University of Wisconsin–Madison. He’s also one of several scientists who’ve been taking a close look at plant behavior. They’re finding that though plants seem still and quiet, they’re actually quite busy.

And what they’re busy doing is pretty amazing.

In the 1980s, botanists first found signs that plants communicate with each other. In one early experiment, hurt trees seemed to warn their neighbors of danger. [Continue reading…]