Plants are People, Too

What Can Plants Do?

I haven’t written a blog post since 2017. I’ve missed it, but, well, life has intervened. But, I’ve just read The Light Eaters, by Zöe Schlanger, a book describing a tidal wave of new thinking about plant behavior, and it has moved me to write.  It’s a New York Times bestseller.  It’s exciting stuff.  

Schlanger writes of research on plants that seem to make decisions, that plan ahead, plants that anticipate where light will be when, altruistic plants, plants that treat close kin better than distant kin or unrelated plants, vines that can mimic the plants they are parasitizing, plants that seem to have some way to “see,” though it’s not at all clear what the mechanism would be, she describes eusocial plants, in which, like bees, some contribute to the survival of others without reproducing themselves, plants that emit the exact chemical to attract parasites of insects that have attacked them, roots that seem to forage.  Ultimately, she wonders whether plants might have the equivalent of a brain, a centralized organizing something.  Many others ponder the same question.  Schlanger eventually asks if the entire plant is equivalent to a brain but, again, the mechanism is a puzzle.  

And there’s so much more.  

The author is very measured in her discussion of what all these new findings might mean.  She cautions about the importance of the traditional scientific method and of questioning results. She reminds us that The Secret Life of Plants, by Tomkins and Bird, published in 1973, was an “irresponsible, best-selling book that nearly snuffed out the field for good.” That book told us that plants have emotions, they prefer Beethoven to rock-and-roll, they can read our minds, and so on.  It was quickly debunked.  

Serious botanists who are thinking about plant behavior these days want to be very careful not to be taken for similar fantasists.  The young field of plant neurobiology applies generally accepted methods to ask how plants process the information they glean from their environment, and it’s these kinds of results that Schlanger reports in her book.

Schlanger is a journalist.  She’s not producing new findings herself, she’s writing about them, as are many others.  A June 11 essay by Rachael Petersen in Aeon asks “Do Plants Have Minds?”  She writes about Gustav Theodor Fechner, a 19th century intellectual from Saxony who contemplated this question.  

He reminds me that the best way to apprehend the unseen in plants is to take off the blindfold and look. He reminds me that what we stand to gain by looking at nature with new eyes is nothing short of the world, and nothing short of each other.

Looking at nature with new eyes seems to be just what’s happening in much of Botany.   

But, there are cautions.  E.g., an April 23 piece by Daniel Immerwahr, in The Guardian, warns that a lot of the data are being over-interpreted (the importance of the underground fungal network between trees, in particular) but that there are many interesting discoveries being made. And, he writes respectfully of Schlanger’s book.  

So, the question of what to make of all these new observations of plant behavior is in the air but we are far from a deep understanding.  I like this Wikipedia discussion of the Chilean Boquila trifoliolata plant, a vine that mimics other plants, even plants it didn’t evolve anywhere near, which Schlanger discusses at length, and even visits in Chile. 

The exact mechanism by which mimicry occurs is not well understood but may involve chemical, odor, genetic, metagenomic, transcriptomic, proteomic, metabolomic, epigenetic, and/or microbial cues to identify and mimic the species it is attached to.

It would seem that the inexact mechanism by which mimicry occurs is not well understood, either.