A photo of three tomato plants, the sounds of which are recorded in a greenhouse. – OHAD LEWIN-EPSTEIN
MADRID, March 30 (EUROPA PRESS) –
Israeli researchers have demonstrated that stressed tomato and tobacco plants, due to dehydration or because their stems have dried out, They emit sounds at a volume comparable to that of a conversation.
The frequency of these sounds is too high for our ears to hear, but they can likely be heard by insects, other mammals, and possibly other plants. as published in the journal ‘Cell’.
“Even in a quiet field, there are sounds that we don’t hear that carry information,” says Lilach Hadany, an evolutionary biologist and theorist at Tel Aviv University. “There are animals that can hear these sounds. So there’s potential for a lot of sonic interaction.”
Although ultrasonic vibrations have already been recorded in plants, this is the first evidence that they are airborne, making them more relevant to other organisms in the environment.
“Plants constantly interact with insects and other animals, and many of these organisms use sound to communicate, Therefore, it would be highly suboptimal for plants not to use sound at all,” Hadany explained.
Researchers used microphones to record healthy and stressed tomato and tobacco plants, first in a soundproof acoustic chamber and then in a noisier greenhouse. They stressed the plants in two ways: do not water for several days and cut off the stems.
After recording the plants, the researchers trained a machine learning algorithm to distinguish between unstressed plants, thirsty plants, and pruned plants.
The team found that stressed plants make more noise than unstressed ones. A single stressed plant will make between 30 and 50 of these clicks per hour at seemingly random intervals, while unstressed plants will make much fewer noises. “When tomatoes aren’t stressed, they’re very calm.” Hadany assured.
The water-stressed plants began making sounds before they were visibly dehydrated, with the frequency of sounds peaking after 5 days without water before decreasing again when the plants dried out completely.
The type of sounds emitted varied depending on the cause of the stress. The machine learning algorithm could accurately distinguish between dehydration and shear stress and he could also tell if the sounds were coming from a tomato or tobacco plant.
Although the study focused on tomato and tobacco plants due to their ease of cultivation and standardization in the laboratory, the research team also included other plant species. “We have discovered that many plants – corn, wheat, grapes and cacti, for example – make noises when they are stressed.” Says Hadani.
The exact mechanism behind these sounds is unclear, but researchers suspect it may be due to the formation and bursting of air bubbles in the plant’s vasculature, a process called cavitation.
It’s also unclear whether plants make these sounds to communicate with other organisms, but the fact that they exist has major ecological and evolutionary implications. “Other organisms may have evolved to hear and respond to these sounds. emphasizes Hadany. For example, a moth trying to lay eggs on a plant or an animal trying to eat a plant might use sound to guide its decision.”
Other plants might also be listening and benefiting from the sounds. It is known from previous research that plants can react to sounds and vibrations. Hadany and several other team members previously showed that plants increase the concentration of sugars in their nectar when they ‘hear’ sounds made by pollinators, and other studies have shown that plants change their gene expression in response to sounds.
“If other plants have information about stress before it actually occurs, they could prepare for itHadany reasons.
According to the authors, the sound recordings of the plants could be used in agricultural irrigation systems to monitor the hydration status of plants and help distribute water more efficiently.
“We know there are a lot of ultrasound scans. –every time you use a microphone, you discover that many things make sounds that humans cannot hear–, But the fact that plants make these sounds opens up whole new possibilities for communicating, listening, and using these sounds,” says co-lead author Yossi Yovel, a neuroecologist at Tel Aviv University.
“Now that we know that plants make sounds, the next question is: who might be listening?” he asks. “We’re currently studying the responses of other organisms, both animals and plants, to these sounds, and we’re exploring too our ability to recognize and interpret sounds in completely natural environments.