How plants talk when we’re not around

Photo: Mimosa pudica, the “shameful plant”, by Suyash.dwivedi, CC BY-SA 4.0 via Wikimedia Commons.

A real surprise in recent decades has been the discovery that plants have nervous systems like animals and use some of the same compounds in communications – for example, TMAO to relieve stress and glutamate to speed up transmission.

Biologist Peter Rogers recently highlighted that the similarities may shed some light on anesthesia-related issues. Surprisingly, it is possible to anesthetize a plant. The shameful plant (mimosa pudica) demonstrated that:

Thirty years after the beginnings of anesthesia in the operating room, Claude Bernard, a French physiologist, demonstrated that the shameful plant (mimosa pudica), which shyly folds in on itself when touched, was unresponsive to touch after exposure to ether, a commonly used anesthetic. The plant also folds in on itself at night, but this movement was unaffected by anesthesia. Bernard concluded that anesthesia does not inhibit the ability to move; on the contrary, it inhibits the ability of the plant to sense its environment. That is to say, the anesthesia blocks consciousness…

PIERRE ROGERSHOW VENUS FLYTRAPS GIVES SCIENTISTS INSIGHTS INTO CONSCIOUSNESS AND ANESTHESIA” TO THINK BIG (MARCH 27, 2022)

It won’t hurt

In 2017, anesthesia was again attempted on a plant, this time the Venus flytrap:

According to [plant physiology expert Rainer] Hedrich, the Venus flytraps remember when they’re hit. When the prey lands on the plant’s trap, it brushes against a sensory hair. The hair triggers an electrical impulse and releases a wave of signal molecules through the trap. After two pulses, the trap closes and imprisons the animal prey. After five pulses, the plant produces digestive enzymes. Because anesthesia disrupts memory in animals, Hedrich theorized that anesthesia prevented the plant from remembering every stimulation.

To test this, Hedrich determined whether anesthetized flytraps still release signaling molecules. They found that the sensory hairs still released the signal molecule when stimulated, but the signal did not propagate into the trap. In an animal, this is similar to local pain receptors which detect pain and release local pain signals, but these signals never reach the brain.

The Venus flytrap’s response to anesthesia suggests that anesthesia affects the plant at the cellular and organ level, as in animals. And that makes it a model for studying general questions related to anesthesia and even consciousness.

PIERRE ROGERSHOW VENUS FLYTRAPS GIVES SCIENTISTS INSIGHTS INTO CONSCIOUSNESS AND ANESTHESIA” TO THINK BIG (MARCH 27, 2022)

Well, “consciousness” goes a bit far, so we better understand what we mean by that. With plants, as with, say, the worms, there could be a vast network of communication without any real consciousness in the sense of an “I” in there. The effect would be roughly similar to a “smart” building, although much more complex. In other words, communications are very sensitive and extensive, whether someone is actually “at home” or not.

How Plants Communicate

Yet the ways in which plants communicate are remarkable. For example, a researcher tells us that plants can use RNA to “talk” to neighbors, affecting their gene expression. This was a rather unexpected discovery:

Why would one plant need to affect the gene expression of another plant? One possibility, Perata posits, is that “sharing information by exchanging RNA would allow plants under stress to warn neighboring plants, not yet affected by stress.” Competition could be another explanation, he writes; for example, if a plant releasing miRNAs “could inhibit the physiological functions of a neighboring plant”, it could gain “a competitive advantage in resource use”. …

[Plant molecular geneticist Hailing]Jin adds that these new findings open up a lot of new questions, and there’s probably a lot more to learn about the role of RNA in plant communication. What we currently know is only the “tip of the iceberg”, she concludes.

ALEJANDRA MANJARREZPLANTS USE RNA TO TALK TO NEIGHBORS” TO THE SCIENTIST (OCTOBER 21, 2021)

There are also many plant communications via fungal networks:

Simple answers to the facts of nature help the plant learn; for example, response to the position of the sun (heliotropism)response to recent temperature changes (vernalization)losing or gaining a response to a stimulus (habituation/dishabituation)and associating one stimulus with another (associative learning). Yes, these last two items are also studied in animal and human psychology.

Read more on The mind matterspublished by the Bradley Center for Natural and Artificial Intelligence at the Discovery Institute.