Scientists have revealed the noise plants make when they are 'stressed' amid a long-running debate over the issue.

It was found that plants emit sounds not detectable by the human ear because of how high the frequencies are.

However, researchers believe the noises can be heard by insects, certain mammals and other plants.

Prof Lilach Hadany, an evolutionary biologist and theoretician at Tel Aviv University in Israel, said: “Apparently, an idyllic field of flowers can be a rather noisy place.

The Herald: (PA) Researchers have settled a long-running debate in science amid plant sound discovery (PA) Researchers have settled a long-running debate in science amid plant sound discovery (Image: PA)

“It’s just that we can’t hear the sounds.”

New research proves plant sounds travel through the air 

While scientists were aware of vibrations being recorded from plants, this is the first time researchers have been able to prove that these sounds travel through the air.

Prof Hadany, a senior author on the study, said: “In this study, we resolved a very old scientific controversy: we proved that plants do emit sounds.

“Our findings suggest that the world around us is full of plant sounds and that these sounds contain information – for example about water scarcity or injury.

“We assume that in nature the sounds emitted by plants are detected by creatures nearby, such as bats, rodents, various insects, and possibly also other plants – that can hear the high frequencies and derive relevant information.

“We believe that humans can also utilise this information, given the right tools – such as sensors that tell growers when plants need watering.”

The Herald: (Canva) The scientists made the plants stressed by not watering them for several days(Canva) The scientists made the plants stressed by not watering them for several days (Image: Canva)

What noise do pants make when they are stressed?

When the researchers recorded healthy and stressed tomato and tobacco plants using microphones, they were able to capture ultrasonic sounds between 20 and 250 kilohertz (humans can only detect frequencies of up to 16).

The scientists said the sound a plant makes is that of bubble wrap being popped.

To create the stress, researchers did not water some of the plants for several days and cut off the stems of others.

After obtaining these recordings, they then put these through machine-learning algorithms and were able to differentiate between the tomato and tobacco plants.

The frequency range was lowered so the researchers could hear the popping sounds made by the plants.

Scientists say the mechanism behind how plants make noise is 'unclear'

The scientists said the mechanisms behind how plants emit sound is unclear with the team adding that it was also unclear whether the plants are producing these sounds to communicate with each other.

Prof Hadany added: “It’s possible that other organisms could have evolved to hear and respond to these sounds.

“For example, a moth that intends to lay eggs on a plant or an animal that intends to eat a plant could use the sounds to help guide their decision.”