Plants scream when stressed or hurt – they’re ‘somewhat noisy’: study

Strange but true

by Brook Cato

March 30, 2023 | 9:07 p.m

Mom is the word.

According to research, thirsty or stressed plants make popping sounds that are undetectable to the human ear Published Thursday in the journal Cell.

Tel Aviv University scientists used special microphones to record the ultrasonic sounds produced by tomato and tobacco plants inside a sound-shielded box and greenhouse.

The researchers say they have developed machine learning models to determine the condition of plants, including whether they are suffering from drought or disease, based on detected sounds.

“From previous studies, we know that vibrissae attached to plants record vibrations. But do these vibrations also become airborne sound waves—that is, sounds that can be recorded from a distance? Our study addressed this question, which researchers have been debating for many years,” said the author. Study co-author Lilac Hadani said in a statement.

The researchers say they placed the plants in a box in a basement with no background noise, and placed ultrasonic microphones about 10 centimeters from each specimen.

Emphasis was placed on tomato and tobacco plants, and wheat, maize, cactus, and hibiscus were also studied.

“Before placing the plants in the sound box, we subjected them to different treatments: some plants were not watered for five days, in some their stems were cut off, and in some they were untouched,” Hadani said.

Our goal was to test whether plants make sounds, and whether those sounds are affected in any way by the state of the plant. Our recordings indicated that the plants in our experiment made sounds at frequencies of 40-80 kilohertz. “

The maximum frequency detected by an adult is about 16 kilohertz.

The researchers found that unstressed plants typically made less than one sound per hour, while dehydrated and injured plants produced dozens of sounds every hour.

The team noted that clicks could be detected even when the plants were placed in a noisy greenhouse.

“We hypothesize that in nature, sounds made by plants are detected by nearby organisms, such as bats, rodents, various insects, and possibly also other plants — that can hear higher frequencies and elicit relevant information,” Hadani said.

“We think humans could also benefit from this information, should the right tools be available — such as sensors that tell farmers when plants need watering.”

Hadani quipped, “Apparently, a perfect field of flowers can be a rather noisy place. It’s just that we can’t hear sounds.”

Scientists not involved in the new research caution that there is no evidence that the sounds produced by plants are a form of communication.

“This finding adds to what we know about plant responses to stress. It is a useful contribution to the field and to our general appreciation that plants are responsive organisms capable of evolving behaviors,” Richard Karpan, a professor who studies interactions between herbivores and host plants, says. he told CNN.

“However, this should not be interpreted as showing that plants actively communicate by making sounds,” Karpan added.