Resarchers in 2011 discovered grain roots transmitting noise.
By Tom Baughn Master Gardener
It is not a question of whether plants communicate, only how and how much. Scientific research on plant communication is in its infancy but has already fostered a paradigm shift.
Communication is multi-faceted. Even humans employ much more than a spoken language. The other senses also communicate. We see, and thus read, facial expressions, hand gestures, even posture. A Realtor may employ the aroma of cookies baking during an open house, to encourage potential buyers to feel at home. We communicate more than mere verbs and nouns when we hug a grieving friend.
The research by Dr. Monica Gagliano at the University of Western Australia indicates that plants can learn by the sensation of touch, learn and remember. Plants can even send electrical signals and see different wave lengths.
A big question is how much communication exists between living things that we simply do not recognize. Plants first made their “voices” heard in 2011 at a Bristol, England, university laboratory. Dr. Gagliano, in collaboration with researchers in Bristol and Florence, discovered that roots of grain seedling were crackling at 220 hertz. Indeed, when another group of seedling roots were exposed to that sound, their roots oriented in that direction.
In trees, the xylem cells that transport water form a line that rises upwards in the tree, similar to a human windpipe. When a drought interrupts the flow of water in a tree, vibrations occur in those empty xylem cells that was measured in the ultrasonic range by scientists at the Swiss Federal Institute for Forest, Snow and Landscape Research. Renowned author Peter Wohlleben wonders if that sound is detected by other trees, which may not yet be suffering from drought, but then take defensive action.
Humans use perfumes and deodorants to communicate. Science has long since known that plants use fragrances to attract pollinators. Yet, we now ask how much more plants are communicating using scent and smell. Using chemical analysis of an insect’s saliva, trees can identify the specific attacker. They send toxins to their leaves and use scents to communicate the presence of danger to other trees, which then mimic the same actions. Using scents, the trees also summon the right predatory insects to counter-attack the offender, according to Mr. Wohlleben.
Pulitzer Prize winner Richard Powers poetically highlights what is occurring below our feet, when he spoke to humans on behalf of plants: “Your kind never sees us whole. You miss the half of it, and more. There’s always as much belowground as above.”
Derived from Dr. Suzanne Simard’s studies, scientists describe a “wood wide web” of fungal filaments, known as mycelium, that cover miles of healthy forests. These fungal networks are not only sending chemical and electrical signals, they are transferring nutrients from trees that have an abundance, to those in need, according to the Institute for Environmental Research at Aachen University. The fungi, which have wrapped themselves around the root tips, produce plant hormones that communicate forest conditions to the tree roots, that in turn control the chemical activity of a tree. Modern science has only begun to understand these dynamics largely because of the complexity of life in forest soil.
We have literally just scratched the surface in understanding the complexity of plant interaction with the rest of the world. What will scientists learn next about the sounds and chemicals plants use to communicate with each other and the environment?
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