Science has shown that when a plant is cut or dried, it changes color, shape, and even smell. But what has been discovered now is that it also emits sounds.
The research is led by Itzhak Khait of Tel Aviv University in Israel. He has shown that plants emit ultrasounds, detectable from several meters away when they are stressed.
His theory is that they could give information to other plants and animals about their condition.
The research has been carried out with tomato and tobacco plants.
The researchers placed microphones capable of detecting ultrasonic frequencies at 10 centimeters from tomato and tobacco plants.
Then they stopped watering them or cut off their stems.
In the range of 20 to 150 kilohertz, plants that were healthy and had not been tampered with made occasional noises, less than one per hour on average.
But when they were cut, tobacco made 14 sounds in an hour and tomatoes made 25. In another experiment, the plants were left without water for 10 days. Tobacco 'squeaked' 10 times an hour and tomatoes 35 times. According to the researchers, these sounds are not audible to humans but are audible to animals such as mice and bats. These sounds are formed like this: water travels through the xylem tubes of plants. As the water moves, bubbles are formed and explode, generating small vibrations, a process called cavitation.
Israeli experts believe that by 'listening' to the plants, irrigation could be optimized and up to 50% of the water used could be saved.