What a Plant Knows by Daniel Chamovitz

Cover of What A Plant KnowsIf you’re looking to show doubters that plants are fascinating then a good starting point is Daniel Chamovitz‘s What a Plant Knows. I was a bit wary of the book at the title made it sound a bit twee. In fact the book is an accessible and extensive exploration of how plants react to their environment. They key is what exactly Chamovitz means when he says that a plant knows something.

For example the chapter What a Plant Sees is clear that plants don’t see like you or I. However, they do respond and react to light. Chamovitz talks about human eyes and the various kinds of rhodopsin and photopsin in the eye. He then talks about sensors in a plant and in what ways they’re similar and in what ways they’re different. When he was talking about all the different sensors in Arabidopsis, my initial reaction was that there’s a lot more going on with light than in my eye. The next page, Chamovitz writes that while a human eye and plant’s sense of light aren’t the same, in some ways you can say that a plant has a more complex understanding of light.

A similar thing happened in the chapter What a Plant Smells. Here Chamovitz talks about reactions to chemicals in the atmosphere and in particular those given off by damaged leaves. This has been proposed as a way that plants ‘talk’ to each other. My own feeling reading this was that it could be an internal signal for the plant and other plants receive it by being close to the injured plant. This would be something almost like eavesdropping on an internal monologue and not intent. A couple of pages later Chamovitz raises this very possibility and then goes on to explain various experiments done to test if this is what’s happening.

If this kind of foreshadowing happened once then it could be coincidence. But with it happening again it’s clear that the narrative has been very carefully planned. Yet it doesn’t feel contrived. There’s no sense Chamovitz is holding anything back to create a ‘ta-dah!’ moment. In fact I was struck by the clarity of the writing.

The hook of looking at correlates for human senses for plants could easily risk fixing the evidence to a convenient narrative mould. This doesn’t happen. What a Plant Hears demonstrates this. Everyone has heard of the experiments that plants prefer Mozart to Motorhead. Chamovitz argues that while they have results, these are bad experiments. He shows why they may get results, and why other experiments suggest that plants are entirely deaf. This is the only part of the book where I could suggest something is missing.

There is recent research showing plants avoid noisier parts of a city. In fact what is happening is that their seeds are dispersed by animals, so the plants themselves are not reacting to the noise. It’s the animals carrying them. It’s another example of an apparent reaction to sound that isn’t. But given that the news story I’ve found dates from November 2012, and the book came out well before that, it’s not a fair criticism. In fact it points to how active a research area Chamovitz is covering.

The book concludes with a discussion of if or how plants are aware. This includes a discussion of the controversial idea of plant neurobiology and Trewavas’s paper Aspects of Plant Intelligence (which you can read free). By the time you get here this could be essential reading if you want to eat salad without guilt.

I picked up the Kindle version and whoever formatted it did a much better job than many science books I’ve read on it. There are no regular typos where it looks like someone simply hasn’t checked the formatting. It does end at 56%, which is mildly jarring on a Kindle. In a paper book this would reinforce how well referenced and noted the book is.

All in all, for this non-botanist, it was an excellent read. Once I finished the book I had a look to see if Chamovitz had any other pop-science books out. That’s a good result.

You can search for a copy in a local library at WorldCat or read more reviews at LibraryThing or GoodReads.


FoPDWe’re celebrating Fascination of Plants Day today on AoB Blog. As the day progresses these links will become live:

  • 09:00: Welcome to Fascination of Plants Day
    What is Fascination of Plants Day? And more importantly, what happens when you pull apart a cell with lasers?
  • 13:00: What a Plant Knows by Daniel Chamovitz
    That’s this entry, you could read it again, but you’d be better off reading the book.
  • 17:00: Will Martian cuisine have a terrifying secret?
    The colonists for Mars One will venture into a hostile environment farther from their families than any human has gone before. It’s a difficult life, but one that might be harder still when they see what’s for lunch.
  • 21:00: 10 Plants used to spice up sex
    Spice is a bit of a give-away that some plants have been used as aphrodisiacs but you might be surprised at what common plants have been used to ignite desire.
  • And Annals of Botany brought you one of the most downloaded modern reports of plant intelligence: Tony Trewavas from Edinburgh wrote “Intelligence is not a term commonly used when plants are discussed. However, I believe that this is an omission based not on a true assessment of the ability of plants to compute complex aspects of their environment, but solely a reflection of a sessile lifestyle.” He also speculates about teaching plants – see http://aob.oxfordjournals.org/content/92/1/1.long

    Richard Firn didn’t agree: http://aob.oxfordjournals.org/content/93/4/345.full