Plants complain when stressed: Harvard and Tel Aviv scientists discovered | They emit sounds that are difficult for people to perceive

2023-04-10 19:40:00

Plants that go through stressful situations, such as lack of water or having cut stems, produce about forty sounds per hour, while those that are well hydrated remain quieter, with only one sound per hour. The statement was included in a work carried out by scientists from Harvard and Tel-Aviv University and recently published in the prestigious Cell magazine.

Now, the question that immediately arises is: if plants make noise, why can’t humans generally hear them? The reason, from the perspective of these specialists, is that they are emitted at a frequency that is difficult to perceive. In fact, they are so high pitched that very few people, and in specific situations, can hear them. However, some animals can hear thirsty plants: bats, mice, and moths could potentially live in a world full of vegetable sounds.

How to hear the moans

To listen to the plants, scientists from Tel-Aviv University in Israel placed tobacco and tomato plants in small boxes equipped with microphones. These devices picked up any noise, including noise that the researchers couldn’t hear. As a result, the sounds were particularly evident in the cases of the plants that were stressed due to lack of water or a recent cut. Along these lines, what are these sounds like? According to the researchers, if sounds are slowed down and sped up, they sound like popcorn when it explodes in a pot.

It is evident that plants do not have vocal cords. Under this premise, the theory about how they make these sounds is based on their xilema: The tubes that carry water and nutrients from their roots to their stems and leaves. Like water being sucked through a light bulb, when an air bubble ruptures, the clicking noise. The appearance of air bubbles is more likely during stress due to lack of water, when these sounds are more frequent. However, the researchers clarify that, to know the exact mechanism, more studies are required.

In everything is artificial intelligence

The scientists developed a algorithm that allowed to deduce if a plant had been cut or presented stress due to dehydration from the sounds he was making. They managed to obtain 70 percent precision, with which the state of the crops could be monitored thanks to the sounds that are emitted.

To validate this way of measuring stress, the team of scientists recorded the sounds of plants in a greenhouse. After filtering the noises of the environment, the murmurs of the plants remained. The authors of the scientific work thus learned that not only tobacco and tomato plants made sounds but also those that make grapes for wine.

Scientists managed to understand the sounds that plants make. Now the question is, can they hear? In previous work, they had observed that nocturnal primroses they release sweeter nectar when exposed to the sound of a flying bee. Although more studies remain to confirm this, the noises of plants are an important characteristic of ecosystems that could influence the behavior of animals.