Frankenstein’s garden is not something most of us have ever heard of, let alone thought about, but the concept arose about the same time as Mary Shelley’s novel “Frankenstein” was published.
Around the time the scientist, who inspired Mary Shelley’s novel, was busy electrocuting live animals and dead prisoners, several of his contemporaries were doing the same to perennials and root vegetables. Just as these 18th Century forays into electrical stimulation purported to make the human body more robust (by delivering it from maladies ranging from paralysis and depression to diarrhoea and venereal disease), they were also investigating electricity’s use for the betterment of plant life. Experiments on electrified gardens were alleged to produce a range of benefits, from brighter flowers to tastier fruit. However, by the end of the 19th Century, respectable science had largely jettisoned both ideas.
More than a century on, better tools and new insights are reanimating the study of electricity’s effects on biology. Early animal experiments have evolved over the past 200 years into real understanding, and have led to promising electrical medicine. Similarly, the old vegetable experiments are being exhumed to see what they may yield in the plant and food worlds. Maybe the new understanding could even improve 21st Century gardens.
The first hints that electric shocks might have a dramatic impact on crops came not from any human intervention but from nature itself. After a lightning storm, according to longstanding Japanese farming lore, mushrooms would proliferate madly. But you couldn’t exactly call down lightning on demand to confirm this experimentally. Until, that is, the 1740s, when various new devices allowed scientists to store and deploy this still-mysterious phenomena of “electricity” for the first time.
Soon deploying electricity as a gardening aid became a hot topic. Pierre Bertholon de Saint-Lazare, a French physicist and philosopher, collected many of his contemporaries’ plant experiments into a library, De L’électricité des Végétaux. Among other claims, flowers were alleged to bloom earlier after electrification. Similarly, electrifying fruit reportedly hastened the ripeness of their smell and taste. Bertholon even invented an “Electro-vegeto-meter”, which mimicked lightning in small doses and could “electrify” entire gardens. It was called “electrical manure”. Frankenstein’s garden was coming of age.
Not everyone was convinced. Things went badly after Jan Ingenhousz, the Dutch-British physiologist who discovered photosynthesis, availed himself of an electro-vegeto-meter of his own to use on his garden – and it promptly shrivelled up all his plants. He concluded that Bertholon’s electrical manure was, well, manure. Interest in electroculture gradually waned.
Enter Charles Darwin. His grandfather had been convinced that electricity could hasten the growth of plants – but Charles Darwin’s contention was built on more solid scientific ground. He believed electricity to be a fundamental aspect of plant physiology, the same way the neurophysiologists of the 19th Century were starting to show how electric signals are the fundamental underpinning of the human nervous system signals that let us think, feel and move.
One friend of Darwin, a physiologist and botanist whose expertise straddled the plant and animal kingdoms, suggested they examine specific odd plants, like the Venus Flytrap, for the same kinds of “nervous” electrical changes that physiologists had recently identified as animating animal muscles. They found them. The published results showed that when the Venus Flytrap slammed shut, for example, it was accompanied by activity that looked remarkably similar to animal electricity.
A couple of decades later, an Indian engineer called Jagadis Chandra Bose revisited Darwin’s question. He was particularly curious about Mimosa pudica, a little fern-like perennial, which folds up when touched. Sure enough, an electrometer revealed electrical activity just before the plant folded. Bose’s curiosity was triggered. In 1901, he reported strong electrical signals in a slew of ordinary plants, including rhubarb and horse radish. Over the next decades these findings were extended to onions, trees, and pretty much every member of the plant kingdom.
All of this went largely unexplained until the late 20th century, when neuroscience tools revealed that plant cells use electrical charges to manage their internal communications, just as animal cells do. Research conducted in the late 1990s demonstrated that plants responded electrically to different stimuli, including light, temperature, touch, and injury. This aligned with insights from chemical plant communication, which suggested that plants can sense danger, communicate with other plants, and call on animals for help. Corn, for example, can summon wasps to attack the kinds of caterpillars that attack corn.
But plants don’t just use these signals to talk to themselves about their internal state: they may also be talking to one another. Some believe such communications can travel through a network of fungal filaments that are ubiquitous in soil and appear to act as electrical circuitry. Recent experiments on Aspen Tree forests indicate that thousands of trees are actually one tree, all interconnected.
This has raised a new prospect. Could we eavesdrop on plants, and decode these electrical signals? Could we find out whether the plants are sitting comfortably – are they too hot or too cold? Do they need more nutrients from the soil? Could they give us an early warning that they are being attacked by pathogens?
It raises a tantalising prospect – we may be about to find out what our vegetables are “thinking”.
Fascinating! Not quite Frankenstein’s garden, but something far more interesting.
