Lessons from Plants in Pain, or What We Talk About When We Talk to Ourselves

December 14th, 2011 | Meera

Roald Dahl, sovereign of the strange idea played out in matter-of-fact sentences, once wrote a story about a man named Klausner who invents a sound machine. With it he’s able to hear rarefied notes—tremors of the air that otherwise range, like so many things, outside the limits of human perception. When he turns on his invention, Klausner finds himself initiated into an entire universe he hadn’t known existed: a universe of plant communication.

You might think, on the face of it, that this would be a fine and lovely thing. You might think of how you generally experience the green and the growing, and imagine Klausner entering a soundscape filled with music, strains that match the beauty of a field of wildflowers or the elegance of autumn leaves. But instead, he mostly apprehends the noises of plants in distress. “Fierce grinding discords” fall on his ears: he’s shocked by the shrieks that roses make when they’re clipped off the bush. He’s tormented by pity when he hears the awful moans of a tree trunk split by his own axe.

Dahl leaves the question of whether the machine really works open to interpretation—but what I like about the story doesn’t rest on the definition of Klausner as either brilliant or insane. The thing that’s stayed with me, long years after I first read The Sound Machine, is Dahl’s bleak view of what speaks loudest in this world, what he thinks drives the “speech” of all living things—and that is pain.

*******

343 (Mimosa plant, before)

Most disasters, even if they’re built on long and quiet years of brewing, eventually befall us with what feels like too little warning. A stroke slams down upon the pathway blood must take to brain, a guillotine that splits a thought in two. Your partner’s eyes, warm as summer lakes, freeze over for no reason you can fathom. A midnight switchblade sticks its cutting edge between your ribs; you gasp awake, pinned by the sharp awareness that you’re inside the wrong life. Tomorrow you might lose your job, your home. Be diagnosed with cancer. Even if you know the air is humid with the vapors of oncoming injuries, each one remains invisible until the day it’s churned into a storm.

I don’t think we’d be better off if we could see the future. I’m pretty sure I, anyway, would be flattened by the weight of full omniscience. But some small bit of notice, a clear advisory or two—watch out, here’s danger on the way!—now that, I’d take. Wouldn’t you? I think that wish must have something to do with why so many of us sit ourselves down to write quite undeliverable letters to the people we once were—an act that’s whimsical and sweet, and yet somehow forlorn.

Maybe it’s also why I’ve come to be, especially of late, a great collector of stories about other people’s hurts. (A cheerful philately.) If you’ve been wounded, come and bend my ear. I want to hear your warnings. And sometimes I eavesdrop on damages that strangers speak of. Years ago I spent almost half an hour lingering over my coffee—which was bad—because the girl at the table next to mine, fresh off her honeymoon, was wiping hot tears from her face and telling her companion how miserable she was to be married. She wasn’t my friend. It wasn’t my problem. And I’m not at all proud to have been riveted. But it was impossible not to be. My body rang (unobtrusively, I hope) with borrowed sorrow, and I still recall her cadences.

I think that moment meant so much to me because, respectfully, Tolstoy was not entirely correct about unhappiness. Life doesn’t feel the need to plan new slights and sicknesses to suit each one of us. Its threats recycle. I’m a realist: I know that, private though they feel, my troubles hover at the average, coinciding with those of my species. Whatever has battered some other Homo sapiens may soon come for me, and I would like to start preparing my defenses.

If this sounds ghoulish to you, well. I understand. But you should know that I am not alone in paying close attention to the suffering of my peers for my own sake. I stand with graceful trees: with willows, alders, poplars, sugar maples. The sweetest and most useful crops, as well—pea pods, beans, tomatoes, cotton—are selfish just like me. And ears of barley, ears of corn—these listen, too, to their beleaguered neighbors.

Klausner (tender soul!) was driven nearly mad by sadness when he overheard plant pain. He called a doctor for his broken tree and made him paint iodine in the wound. Plants themselves know better what to do.

*******

It was in the early 1980s that a few scientists first began to report on trees that seemed to send each other stress signals. One was a zoologist named David Rhoades, at the time studying Red alder (Alnus rubra) and Sitka willow (Salix sitchensis) defense mechanisms at the University of Washington. Rhoades fed caterpillars leaves from trees their brethren had previously attacked. He found that they began to lose their appetites, and often died prematurely. Presumably this was because of some chemical compound the trees were able to release into their leaves as a form of rapid resistance—precisely the kind of thing he’d been looking for.

But Rhoades was surprised to discover that the very same thing happened to caterpillars fed the leaves of undamaged control trees, planted a little distance away. Could the attacked trees be emitting some kind of pheromonal warning that their counterparts could “hear?” Could they be telling their fellows to put up a fight against their leggy foes?

This study inspired a similar experiment on potted poplars (Populus euroamericana) and sugar maples (Acer saccharum) by a pair of researchers at Dartmouth. Jack Schultz and Ian Baldwin found higher concentrations of mildly toxic compounds called phenols in trees whose leaves they had torn. They saw the same thing when they checked on unscathed trees, after they were exposed to air pumped in from the chamber where the damaged trees were housed.

The scientific community as a whole reacted to these findings with great skepticism, some of which was not undeserved: methodological problems and an over-confident interpretation of statistics tainted both sets of results. But there was also, apparently, not a little ridicule, with some ecologists scoffing over the idea of “talking trees” and animal behaviorists closing ranks around the definition of communication.

In hindsight, this part of the negative response was somewhat less justified. In the first fourteen years that followed Rhoades, Schultz, and Baldwin’s reports, only three studies regarding plant-plant communication were published (perhaps because of the disbelieving atmosphere they would have emerged into). But times have changed. According to this overview of the literature on the subject, that figure increased to nearly 50 papers between 2005 and 2010.

At this point, the evidence that plants can receive, act on, and benefit from specific signals produced by their distressed coequals is pretty compelling. We’ve learned, for instance, that corn seedlings primed with compounds released by damaged plants give off more of their own defense hormones and chemicals when subsequently slashed with a razor blade or painted with caterpillar regurgitant. (Science is cruel.) We’ve learned that certain unrelated species, like sagebrush and tobacco, can interpret each other’s cues about dangers like hungry herbivores or clipper-happy researchers. We’ve even learned that well-watered pea plants, having overheard a warning from a thirsty neighbor, can pass on that message to still other plants, further away—although this game of vegetable Telephone seems to be played through the medium of soil, not air.

In my favorite recent study, which delights me more because of how the plants defend themselves than how they talk about it, Lima beans infested with spider mites—as well as those exposed to leaves from infested plants—react by activating a set of genes that trigger the emission of a volatile organic compound. This compound, in turn, attracts spider mite predators that come and hoover up the pests.

How wonderful is that? I call it very wonderful, especially since our own apartment has witnessed the expiration of a beloved dwarf Meyer lemon tree that succumbed to a spider mite blitzkrieg. If we’d had two trees, I wonder if one could have saved the other?

Maybe what Dahl got wrong was not the thought that pain is the seabed of all our most essential speech. Maybe where he erred was in suggesting that the anguish Klausner heard was simply that: anguish, pure expression with no purpose and no useful end.

I think of myself sitting at a coffee table, leaning in, despite my better judgment, and breathing in the chemistry of someone else’s heartache. In my mind, now, I see it as a moment of anointment, an inoculation. I think this even though I have no way of measuring what changed in me because of it.

Our bodies fail. Our partners leave. We wake up sick, or shipwrecked. Shocked. And I am hungry to be put on guard, to know when something wicked this way comes.

*******

It’s clear that unscathed plants do eavesdrop, like me, on strangers in distress, and make themselves stronger when they hear of trouble. What’s less clear is what is happening for the plant in pain. Is its anguished warning—Watch out, danger!—really meant to serve as counsel to the ones around it? It’s possible, of course, that some plants evolved to give off stress signals altruistically, because neighbors are often kin, and one example keeps the group as a whole safe. But many times, letting a neighbor in on danger makes you more vulnerable. A Lima bean plagued with spider mites might not want its compatriots to be protected by mite-eaters. (One lemon tree might have saved another, but reluctantly.)

Instead of selfless exhortations, the story of plant stress signals seems at once more simple and more strange. The thing is, a plant that’s hurt and sending out a warning is very likely talking to itself.

Most plants have sophisticated vascular systems, and that’s often how they transmit chemical messages. But volatile compounds, diffusing through air, can travel faster than molecules moving against gravity through tiny tubes. Airborne signals also allow parts of a plant that don’t have a direct connection to each other to speak. Why, though, would a plant need to warn itself? What does that even mean? Well, think of this: A caterpillar munching on one leaf will probably move on to another, a little ways off. That second leaf has time—not much, it’s true, but some small span—to put up its own garrison against the tyranny of tearing insects. That second leaf is far from doomed. And it could use some notice. A body needs to take care of itself.

Most disasters befall us with what feels like too little warning. But maybe that’s because, wrapped up in where we hurt right now, we don’t imagine taking steps to care for what is still undamaged. I know; we are not plants, with separate fates for separate parts. When I’m in pain, it feels as if I ache completely, my entire consciousness consumed by one calamity. And yet. Could there be, do you think, something in this selfish signaling? Some way for us to be like willows and like alders?

I’m not entirely sure. But this past year, and nearly two, has felt like injury to me; so now seems like the time to test the case. I’d rather not be Klausner’s roses, crying out futility. I’ll trust instead that there is strong and healthy matter that remains in me, and let the weaker parts speak loudly to them. More importantly, I’ll try to listen and to learn. Because it’s not, I think, too late to start talking to myself.

And you? Ah. If you eavesdrop, let it be.

*******

Mimosa plant, after

Highly recommended further reading: This wonderful article about visionary biologist Chandra Bose, and his experiments in plant sensation and behavior.

14 Responses to “Lessons from Plants in Pain, or What We Talk About When We Talk to Ourselves”

  1. Brian says:

    This is a beautiful piece of writing, Meera. Thanks. It made my morning.

  2. greg says:

    I’m reading this at 4:30 in the morning. I sometimes have nightmares based on old incidents, and it takes a while for me to work up the courage to try to go back to sleep. I suspect my psyche could use a few spider mite predators.

    But I’m not sure I’d actually use them. Here’s an odd thing: I feel like I earned these nightmares. Not that I deserve them, or that they’re justified…but that I’ve earned them by putting myself in a position to have experiences out of which nightmares might arise. And I’m rather glad I’ve had those experiences. I don’t like the nightmares, but each year they’re a little less bad and a little less frequent. So I think it’s a fair trade.

    Although I probably wouldn’t write something this confessional if I wasn’t awake at 4:30 in the morning.

  3. Meera says:

    I say this all the time, but that’s because I think it’s always going to be how I feel: Thank you so much for reading, and for letting me know what you think. It’s like water to me. Most of the time I live in drought conditions.

    And here’s to earning the survival of what harms us.

    Love,
    a pea.

  4. Sarah says:

    This is lovely. I remember reading that Roald Dahl story–not the specifics of it or even that Dahl had written it–but I remembered its kernel of an idea which you made resonate beautifully.

    • Meera says:

      Sarah, thank you. I read your “Frisson of Friction” essay the other day and liked your lede as much as you did. :)

  5. Thom John says:

    This, again, has so many illuminating insights! But I will comment on only these as they touch my own experience of pain, both emotional and physical. First, I found a clear echo, for myself, in your wonderings about that plant with the chance of saving the next leaf. One really can be in a circumstance where although we seem to be one whole body, that body’s components evaluate to separate, distinct, and useable levels of strength, health, and, yes, ability to help other parts function or heal or even die off if that is what they must do. Second, pain does seem to have a way of bringing forth, I won’t say inspiring, communications of both a deeper content and less obvious methods. Subtlety emerges partly because the full nakedness of whatever it is would be too much to absorb. So we whisper. Third, I have seen the other side of exposure to and familiarity with others’ hurts, ailments, trials and tribulations, as they say, and when it piles up, gets too much, becomes the focus overall, the person stops being themselves and becomes the pain instead. I guess as with everything else, moderation is key. But I agree with Donne, and with you!, that we are not islands and best not live like ones. Even if that means eavesdropping sometimes. I thank you for this, greatly. I read it yesterday and now again during a chemotherapy session and there are new things the second time around.

  6. Meera says:

    Dear Thom, I thought of you at certain points while I was writing this. I hope your session is over now, and that you’re feeling okay. Thank *you* for responding with such care, and for this reminder, which I needed: “…the person stops being themselves and becomes the pain instead.”

  7. april says:

    What a beautiful piece of writing… so much to take in and think about. Including the sense that I’m experiencing something like a tree that’s just been warned about the spider mites next door. Thank you!

  8. shoreacres says:

    This is a rich, dense post filled with insight. I especially was struck by this, and the full paragraph which follows: Most disasters, even if they’re built on long and quiet years of brewing, eventually befall us with what feels like too little warning…

    The critical phrase, of course, is “feels like”. More often than we like to admit, the signs, the warnings were there. We simply prefer to ignore them. I made an appointment to see a cardiologist for a baseline workup after the first of the year. Nothing’s wrong, at all. Still, something is “different” – like suddenly hearing water in the bilges of a boat. It’s time to stop, and listen – even if it leads to nothing more than going on.

    As for the plants – there’s a lot of science here I don’t follow. Still, I wonder – could this be the explanation for my compulsion to pot up every bit of trimming from my geraniums, schefflera, Christmas cactus? Perhaps I’m hearing the cries from the amputees, and am trying to atone for the surgeries. ;)

    • Meera says:

      Thank you and thank you, April of the clever email address and Linda of the ever-charming connections. I am still trying to learn my own lesson. It is hard, hard, hard for me to access the parts of myself that are still whole and healthy. I am not very good at it yet. We shall see. Good luck to you both, as we all try to engage in what we can of this strange and lovely early-warning system.

  9. Michele says:

    Hi there, I’m visiting some of the blogs (randomly) of scio12 attendees, and I am so glad I found yours. This is a beautiful piece and fascinating. See you at sci012.
    Michele

    • Meera says:

      Michele, hello, thank you so much for visiting, and I look forward to meeting you! I’m going to find you on Twitter if I can in a moment.

  10. Chuck says:

    Astonishing and beautiful, Meera. And too close to home, in ways, on this end. Just when I think I’ve seen you at your most eloquent you surpass yourself. And when you can take pain and turn it into loveliness such as this piece . . . well, then maybe pain in the world can never really triumph after all. Thank you.

    • Meera says:

      Chuck—sincerely, the fact that you are reading is a very big part of why I keep doing this, even though most of the time it feels like I’m not getting anywhere close to where I aim. I am glad this meant something to you and sorry it hit too close to home. xoxoxo