Who knew that a weed can smell the difference between a tomato plant and wheat, a tobacco plant can sense color, and a Venus flytrap can distinguish between the splash of a raindrop and a fly? Like so much in nature, it’s a matter of survival. Daniel Chamovitz, author of What A Plant Knows: A Field Guide to the Senses and director of the Manna Center for Plant Bioscience at Tel Aviv University, explains why that philodendron on your desk has more “smarts” than you ever imagined. National Geographic Editor at Large Cathy Newman interviewed him for an inside look at the quietly complicated lives of plants.
What was the impetus for the book?
First of all, I was shocked that things I took for granted most people didn’t know. We scientists have done a poor job of communicating. There was a wildly popular, but scientifically anemic book, The Secret Life of Plants, published in the 1970s. I wanted to set the record straight. The truth is so much more exciting than pseudo science.
I wanted to convey the sense that science is an exciting process full of kooky people, amazing people. It’s a social endeavor. Not just one person sitting in a lab.
Plants can sense up from down. They can discern light, color; they have a tactile sense. They sense smells. Isn’t this rather sophisticated for a lower form of life?
It is if you don’t consider that all organisms need to sense their environment in order to survive. Even algae move toward the light to allow for photosynthesis. So we aren’t special in that respect [of having senses]. The only difference is that we are the only ones that think about what we are doing.
Let’s talk about why plants have all those skill sets.
Plants can’t run away. They are rooted. It’s the key to their evolution. Animals can survive by running away.
It’s surprising to learn that tomatoes have 25 per cent more genes than we do.
Plants use their genetic complexity to sense and survive adversity. It’s compensation for the inability to run away.
And, it turns out, we share a lot of the same genetic sequences. So that tulip staring me in the face is more closely related to me than I ever imagined?
On the one hand we have a huge diversity of form. There’s you and a giant oak. But we do have a unity of genetics. Those genes had to evolve from a common ancestor. Of course, we are talking two billion years of history since animals and plants shared a common cell.A Gloriosa daisy flower in a vase. Photograph by Joel Sartore, National Geographic
Let’s talk about some of the shared biology between plants and ourselves.
One of the coolest is our response to light. We respond to light knowing when we should be up and when we should be asleep. Plants respond to light as well, and so we share a circadian clock. Also, plants can respond to mechanical stimulation. A Venus flytrap responds to a fly by generating an electrical signal, in the same way our heart responds to electrical signals to contract.
Is it true that plants don’t care whether you play Mozart or Black Sabbath. They won’t grow faster either way?
There is no real evidence that plants have musical taste. But I wouldn’t be surprised if they respond to vibration.
Let’s talk applications. How does a plant’s ability to see or smell translate into the practical world?
We know that a plant senses light and shade. If plants are crowded next to each other, they sense shade and become tall and spindly. But if you breed a plant blind to the shade, then you can put more plants together, they will put their energy into growing more leaves and fruit, and you can grow more food in a smaller area.
What kind of reaction do hope for in publishing your book?
I am happiest if it makes people rethink their existence.