Researchers record sounds made by plants for the first time

The plant world is not as silent as it seems. Israeli researchers have, for the first time, recorded sounds emitted by plants. Some previous studies had already captured plant vibrations and their acoustic study has been developing for more than 10 years. But here, for the first time, these scientists from the Israeli University of Tel Aviv have been able to record noises emitted by plants.

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Frequency increases with stress

It sounds like a cracking sound or the sound of popcorn popping. Sounds that had to be transformed for us to hear them. Because in nature, they are emitted at high frequencies, imperceptible to the human ear, their frequency exceeding 16 kHz. In this experiment, they could be captured using specific microphones, ultrasonic microphones, installed about 10cm from different plants. Tomato, tobacco, wheat, corn and cactus plants.

And what do these plants tell us? Researchers have not yet been able to translate the messages emitted by the plants. Not yet, but the observation is that their frequency increases with the stress of the plant. Plants in good health which, a priori, lack nothing emit only one sound per hour. Plants that lack water or have damaged foliage or stems can make dozens of these cracking noises per hour. The Israeli scientists, for example, found that tomato plants made little noise when they were watered, but that after four or five days without water, the frequency of the recorded sounds increased.

Tracks for agriculture

The hypothesis is that these sounds are linked to air bubbles that form or expand in the stem when the plant is under stress. This work was published in the scientific journal CELL. In nature, why does a plant warn that it is stressed? Who can pick up this message The researchers assume that these ultra sounds emitted by plants are detected by other living beings nearby: bats, insects, or other plants. They are thus alerted to a lack of water, the presence of diseases or parasites that attack the leaves.

This work will continue but it is already opening up avenues for agriculture. Because by capturing these sounds with suitable microphones, producers could have a finer knowledge, in real time, of the needs of their plantations.