Scientists at Tel Aviv University in Israel have discovered that plants emit sounds in ultrasonic frequencies when they are under stress, outside the range of human hearing. These sounds are described as a polling or clicking noise that increases with distress. Researcher Lilach Hadany, an evolutionary biologist at the university, believes that this could be a way for plants to communicate their distress to the world around them.
Plants interact with insects and other animals on a regular basis and use sound for communication, so it makes sense for them to also produce sounds in some way. The team wanted to investigate whether plants produce sounds when they are stressed, in addition to the visible changes they experience.
The scientists recorded tomato and tobacco plants in stressed and unstressed conditions, using their definition of stress to include instances where plants had their stems cut or were dehydrated. They found that distressed plants emitted high-pitched sounds that were undetectable by humans but could be heard within a radius of over a meter. Unstressed plants did not produce much noise at all; they remained quiet and continued with their usual activities.
While the researchers were able to differentiate between the sounds produced by stressed and unstressed plants, they are still unsure about the exact mechanism through which plants produce these noises. Nevertheless, this study sheds light on an intriguing aspect of plant biology and opens up new possibilities for understanding the ways in which plants communicate with their environment.
