Plants make more noise when stressed, according to a study

Can Plant Sounds Be Used for Communication? Graham Pyke, Bio-Entomologist and Neuroscientist, A Conversation with David Karban

The noises that the plants made were similar to the pop of popcorn being made and bubble wrap bursting, but when they were translated to a human-readable sound, they were a bit different.

So are plant noises an important feature of ecosystems, influencing the behaviour of plants and animals alike? Graham Pyke is a retired Biologist who specializes in environmental science and he said the evidence was not yet clear.

Tobacco and tomato plants were put in boxes with microphones that recorded at a maximum of 25 decibels. (The maximum frequency that a human adult’s ear can detect is about 16 kilohertz.) Some of the plants did not have water for a week, and others had their stems cut.

You can rest assured that the bouquet of cut flowers in your vase is not screaming at you in pain. There is no evidence that the noise produced by the plants is intentional or a form of communication.

We know that plants have responses to stress. It is a useful contribution to the field and to our general appreciation that plants are responsive organisms capable of sophisticated behaviors,” said Richard Karban, a distinguished professor of entomology at University of California, Davis, who studies interactions between herbivores and their host plants. He was not involved in the research.

While the plant sounds are a passive phenomenon, other organisms might be able to use the plant’s audible cues for their own benefit, said sensory ecologist Daniel Robert, a professor of bionanoscience at the University of Bristol’s School of Biological Sciences in the United Kingdom. He was not involved in the research.

For example, he said the sound of a tomato plant in distress could indicate to a female moth that it’s not suitable to lay eggs or feed on it.

A lot of sounds in the world can be heard and used for their own benefits, even if they are not intentional signals. So, the concept of communication is indeed a challenge … does it need to be bi-directional to work and be considered as such?” He said this in an email.

Machine-learning based classification of acoustic emissions in tobacco and tomato plants in a greenhouse: Detection of thirst, unstressed and cut

Tobacco and tomato plants were replanted in a greenhouse environment. After recording plants, the researchers created a machine-learning algorithm that could tell between plants that are thirsty, unstressed and cut.

“The finding that there is information in the acoustic emissions, using neural network classification, is exciting as such (a) technique is fast and can identify data structures that the human eyes or ears cannot,” Robert noted.