It sounds almost like the premise of a B-rated sci-fi movie from the 1970s: researchers injecting plant cells with Prozac, Ritalin and even methamphetamine in an effort to change plant behaviour.
But this isn’t the script for an abandoned sequel of Invasion of the Body Snatchers. In fact, it’s just the kind of experiment that Susan Murch, University of British Columbia chemistry professor and Canadian Research Chair in Natural Products Chemistry, and a growing number of researchers are doing.
Representatives from more than 40 countries gathered last summer at UBC from the International Society of Plant Signalling and Behaviour. Over the past decade or so, some of these researchers have discovered that plants make use of melatonin, serotonin and other biochemicals typically associated in humans as the neurotransmitters that control sleeping patterns or depression and other emotions.
In plants, Murch says these neurotransmitters can regulate things like the growth of roots and may tell the plants when to flower and how to keep time in general. “The curious thing is that plants have melatonin and serotonin. Why do they have them?” she says. “Does it make them fall asleep and wake up in some analogous way?”
She’s been working on a number of experiments where she injects plants with drugs that affect serotonin or melatonin. She found that tampering with these biochemicals can change plant behaviour. On methamphetime, for example, she found that plants grow shoots, but no roots.
The idea of plant behaviour is an innovative concept that hasn’t come about without controversy. Murch says that they had to change the name from “Society of Plant Neurobiology” due to the negative reaction from the science community that arose around the principle that plants had brains.
Murch says that part of the controversy comes because of the language researchers are used to. She says that people used to talk about plants as sentient beings in the past, but at some point, it became unfashionable, thereby limiting the types of investigations scientists would do. In order to broaden the way she conducts experiments, she sometimes works with literary scholar Sonnet L’Abbé to re-examine her approach.
“The idea is that if we think about plants that are completely non-sentient, waiting for something to do something, we will design different experiments. It’s about whether we have an inherent bias in our experiments,” Murch says. “I think there’s a lot of value of exploring the use of language.”
When it comes down to thinking, Murch says that although plants don’t have brains, they have some biochemical processes similar to brains. They can make decisions, respond to environmental stimuli and possibly even learn.
“We’re really interested in learning — if they can learn, that’s really neat.”