Before all the lockdowns, I bought some fresh basil from Trader Joe’s, trimmed off all but the top leaves, clipped the stem at its midpoint, and put the cut end in a little glass vase.
When the basil pushed out fresh baby roots at the end of March, I was transitioning in my isolation from losing it in a bad way — with panic mimicking fever symptoms — to losing it in a good way, falling hard into daydreams and making much-too-elaborate dinners for one.
The little roots were one thing nudging my mental state in the right direction. In them, I perceived something of a message: a song simple and beautiful, banal and profound.
They sang: Life yearns for more.
This clipping, which could have just withered after a rough journey through the Trader Joe’s supply chain, didn’t die. It was trying to survive, and I felt good about it.
These hopeful baby roots were on my mind when I saw a new study, published in the journal New Phytologist, about the beautiful, ordinary, and profound things flowers do after suffering an injury. That is: When many flower species get knocked down, they right themselves. The individual flowers on the stalk will rotate back, as best they can, into a position ideal for pollination.
Like me watching my little roots growing at home, the scientists here made a small — and, one might say, obvious — observation. The difference, though, is that this paper is perhaps the first time this has been documented in the scientific literature, the result of a decade of work.
The paper is also a window into the balancing act of evolution. It’s reassuring to read it now, in springtime, as flowers are blooming and many of us feel like we are not. Look at blossoms, which may seem frail at first glance, and discover resilience.
It’s not often I find the text of an academic article to be riveting and even beautiful. Here, I was hooked: “Virtually no research has addressed response to accidents involving flowers,” ecologists Scott Armbruster and Nathan Muchhala write. “Yet flowering stalks are often subject to accidental collapse, as when a scape blows down in the wind or coarse litter falls onto a stem ...” Great Darwin’s ghost! This is a scientific oversight.
Armbruster and Muchhala wanted to know what happens when a flower is put in peril. Their research here also speaks to the message: Life yearns for more.
Ten years ago, a tree branch fell on some flowers in Australia
Scott Armbruster is a professor at the University in Portsmouth in England, who spoke with me from his own quarantine in a remote corner of the Isle of Wight. There, he’s surrounded by trees and, increasingly, people on nature walks trying to escape the confines of their homes.
Armbruster studies the coevolution of plants and the insects that pollinate them. Such is the delicate balance of evolution: There is a flower optimized for a bee to land on it, and a bee capable of landing on that flower. These partnerships have co-evolved for millions of years, and they exist everywhere in nature. When Charles Darwin, for example, saw an orchid with an 11-inch-deep nectar well, he predicted that there must be an insect with a ridiculously long mouth to reach the sweet stuff. He, of course, was right.
“In many ways, Darwin was my hero as a little kid — and I’ve never outgrown that,” Armbruster says. Like Darwin, Armbruster prefers the type of science that involves adventuring out into the world and making careful observations of life doing its thing. His hypotheses, and his experiments to test them, are derived from that fieldwork.
Ten years ago, Armbruster was out doing fieldwork in Australia when he came across a trigger plant that had suffered an “accident.”
Trigger plants grow like snapdragons do here in the US: They have tall stalks, encrusted with jewel-gorgeous flowers that point outward toward the horizon.
On this day in Australia, a branch had fallen from a tree above, knocking the vertical stem of the trigger plant so that it was lying on the ground. The plant was still alive; its stem didn’t snap. But this is not a good position for the trigger plant to be in.
It’s essential for a trigger plant’s stem to stay right side up so that it can keep its flowers pointing outward. On the flower, “there’s a landing platform that the bumblebee needs to land on, and that needs to be underneath the bumblebee,” Armbruster says. “If the flower was upside down or sideways, it would be much harder for it to land.” (Flowers can either give pollen to, or receive pollen from, an insect. A sideways flower messes up the giving side of the equation, too: If the pollen is placed on the wrong side of a bee, it may never pollinate another flower.)
This trigger plant didn’t take the insult of the tree branch lying down, however. Even though it had been pinned down, Armbruster noticed it had started to rotate its flowers back to the proper position for pollination.
Next, Armbruster wanted to know if he could recreate this artificially. What he saw could have been a fluke So he found a new trigger plant and tied it down, and photographed its flowers every six hours. “Within a day or so the flowers were back in the right orientation,” he says.
Life yearns for more.
Small, beautiful discoveries come to those who are patient and pay attention
Looking through the scientific literature, Armbruster was surprised that no one had documented this small, precious phenomenon before. “I really thought somebody must have at least mentioned it,” he says. “I’m pretty sure it’s just, nobody thought to write it down. I would be very surprised that a good gardener somewhere hasn’t noticed it.” Even Darwin, he says — who made careful observations of flowers opening and closing between day and night — never mentioned flowers reorienting themselves after an injury.
So over the past decade, Armbruster and his colleague Nathan Muchhala, an evolutionary ecologist at the University of Missouri, have been documenting natural instances of this phenomenon in the wild and performing experiments to see if flowers around the world also try to right themselves. (It’s taken so long because this isn’t work they have had funding for. It’s been a side project they’ve tacked on to other fieldwork expeditions.) Their paper contains data on 23 species, from the trigger plants of Australia to bell flowers and heath in the cloud forests of Ecuador to buttercups in Alaska.
Critically, it also contains data on flowers that did not show this adaptation.
Armbruster and Muchhala hypothesized that this adaptation would only be present in flowers that need to be kept in a very precise horizontal orientation to be pollinated.
To understand this, it helps to think a little more closely about flowers and their shapes. Many flowers are classically radially symmetrical, like a sunflower or a tulip. These even shapes allow pollinators to land on them from many angles, which means they are less likely to be devastated when their stems bend, the duo reasoned.
Some flowers, however, are just bilaterally symmetrical — like we are — with one line of symmetry running down the middle. These flowers often rely on a specific orientation for pollinators to be able to land on them. Trigger plants, snapdragons, and orchids show this type of symmetry.
To clarify: This picture (b) is of a flower called mountain larkspur. It’s bilaterally symmetrical. A bee hoping to get at its nectar only has one place to land. See the arrow.
Here is a toad lily (a). It has radial symmetry, and a bee can pollinate it from many approaches.
It turns out the radially symmetrical flowers in the study “had little capacity to reorient their flowers” after an accident, the paper reads, compared to laterally symmetrical ones, like the trigger plants. This suggests that in their evolutionary history, they didn’t need to do this as much to survive.
“What I like most about this study is that they did very simple manipulations — just bending the flowers down,” says Eric LoPresti, an evolutionary biologist at Michigan State University who was not involved in this study. “The simpler the manipulation is, the easier it is, often, to interpret.”
Armbruster is cautious about saying this is the first scientific documentation of the phenomenon. “In some ways, that makes me slightly nervous, but in other ways, it makes me quite pleased that we saw something so obvious that no one bothered to look at closely,” he says. (Stacey Smith, an evolutionary biologist who studies flowers at the University of Colorado Boulder, says in an email that “this is the first study to my knowledge” to show flowers can fix their position after taking some damage.)
And a caveat: This paper is not an exhaustive survey. They only examined those 23 flowering plant species — of the estimated 350,000+ on Earth. In that batch, there were only three types of radially symmetrical flowers. This paper doesn’t — and can’t — say this trait is universal, even among the laterally symmetrical flowers.
“A next step would be to broaden this and find out which radially symmetrical flowers do recover, which bilaterally symmetrical flowers don’t,” LoPresti says. The cases when these results don’t generalize, he says, “is just going to tell us more about the importance of flower orientation.”
The new study finds that it exists, and that it is probably the result of the careful dance of evolution: For millions of years, flowers have had to deal with random chaotic accidents nature thrusts on all living things. Those that have adapted to accidents have survived.
Is it like these plants have a type of “memory” for where their flowers are supposed to be, I asked Armbruster?
“This is not fully known,” he says.
What plants can teach us about resilience
What I’ve been observing in isolation, and what I read in Armbruster’s paper, are some of the most basic things plants do. They are not human, with our complexities, with our troubles. And I’m not saying keeping plants during a pandemic will lead you to profound revelations about nature and our place in it.
I am saying they can be a comfort and sometimes, even, something of a totem of resilience.
“Plants just stay their entire life in one space and have to survive from there,” LoPresti says. That’s not so different from many of us right now. “Seeing how they do it, and how each plant does it differently, is what motivates me.”
Having moved his lab to his home, LoPresti has been passing the time making observations of how the desert poppy plant droops its leaves at night and then perks them up before sunrise. Many plants do this, though scientists aren’t sure why. LoPresti noticed that this behavior was never recorded being observed in the desert poppy. So he’s making notes of it. “I discovered something small, and I’m sure anyone who’s growing plants can discover something rather small like that,” he says.
I have to admit something now: The story about my little basil plant ends poorly. The problem is, I think I tried to plant it in soil before the roots were mature enough. Within a few days of its transplant, the little stalk’s tiny green leaves were brown. It was dying, then dead.
Still, during lockdown, I’m glad I have a little garden of other houseplants to attend to, cultivate, and propagate. Noticing the tiny changes in plants helps, at least, keep track of time. Some days, it feels like I’m not sure how long I’ve been living like this, but I do know there are two inches of roots coming out of a plant clipping that weren’t there before.
I know this isn’t a discovery; botanists have long observed plants’ ability to grow new roots.
But I love the activity of paying attention, trying to imagine what an early botanist, or even Darwin himself, might have thought of the process. Science, at its most romantic, is an exploration. It’s an exciting quest you can join by, at least, just keeping your eyes open. I try to do that more now.
I had the basil failure, but concurrently, I saw something lasting and good. In October, I propagated a plant clipping from a friend of a friend. Since then, it has stayed alive, but it hasn’t grown much at all. At the start of quarantine, I put it beside a bright lamp, hoping the extra energy would provoke something. A patient month later, there’s new growth. Life yearns for more — but sometimes it needs a little help, too.
The comfort of plants is knowing that they, too, are just trying to deal with the shit life gives them. And we can often observe them, in quiet wonder, doing so successfully. And we can feel the pain of loss when they fail. That’s the moral to this story. “Humans have always dealt with, and got on after, a catastrophic event; we compensate in whatever way we have to,” Armbruster says. “And that’s sort of what the plants are doing.”