Plants may lack verbal language, but that doesn’t mean they can’t communicate with one another. Researchers at Saitama University in Japan recently conducted an experiment to observe how some plants send volatile organic compounds to each other via the air, in order to warn of dangers such as pest attacks.

Published in the journal Nature Communications, their study focused on “arabidopsis”, a herbaceous plant from the Brassicaceae family that grows in Europe, Asia, Africa and North America.

Laboratory experiments showed that these plants transmit messages to each other via volatile organic compounds (VOCs) when confronted with a pest attack. These compounds enter the tissues of neighbouring plants, alerting them to the danger and activating their chemical defences.

The secretion of chemical compounds by plants can then make leaves inedible and deter insects from attacking them.

For their research, the authors placed caterpillars on arabidopsis leaves to observe how the plants reacted. In some cases, the plants triggered calcium signalling, which the researchers were able to detect by means of light signals introduced under a microscope using a fluorescent device.

Using this technique, they were able to visualise the transmission of VOCs between plants.

While the fact that plants can communicate with each other to protect themselves has already been scientifically established, this is the first research to demonstrate this visually and to detail the process.

The researchers emphasise the value of such a procedure, saying it could provide a better understanding of this mechanism, and help scientists and farmers protect their plants against insect attacks or bad weather.

However, the ability to transmit information is not the only “hidden” skill of plants: some are capable of emitting ultrasound. A study conducted in Israel and published in March demonstrated that tomato and tobacco plants grown in greenhouses can emit large amounts of ultrasound when they run out of water or are subject to external stress factors – for instance, when their stems are cut.