Plants have “ears”

4 min

We have never talked so much about the intelligence of plants: they would be endowed with memory, a system of improved communication, of sensitivity. The plant neurobiology shows us that these beings without mouth, without nose, without ears, can still exchange, feel and even… hear.

Do plants really have ears? © Getty / borchee

A little less than ten years ago, the team of Australian researcher Monica Gagliano showed that when running noise of water to corn plants, their roots were visibly bending: they were getting closer of the sound source. In other words: the plant spots the water that is flowing, without seeing it or touching it! It was the first time we observed a plant in full listening. Since then we can confirm that plants have “ears”.

Cornfield © Getty / Gary J Weathers

Ears to defend themselves…

Thale Crete (a plant that is commonly found on city sidewalks) listens to better defend itself: when it hears a caterpillar chewing its leaves, it immediately releases toxic molecules to interrupt the aggression. The plant responds specifically to the predator.

…or to collaborate better

Glossophage Pallas is a species of Cuban bat that flies over the flowers. They feast on their nectar, they come to pump with their tongue at full speed, without even asking.

Some flowers are able to call bats: researchers have discovered that a vine flower has adapted the shape of its leaf so that it can return the ultrasound to the ear of the bats ears to indicate its presence. Thanks to the calls of the vine leaf, the bat can visit twice more in one night and the plant gains an effective pollinator… A good example of synergy.

What part of the flower allows it to listen?

A study has been buzzing in the scientific community recently: an Israeli team has uncovered another system of collaboration. The researchers published a recording from the buzzing of honeybees flying ten centimeters above a hundred evening primrose, a herbaceous small yellow flower. As a result, the production of nectar exploded and in just three minutes, the sugar concentration of the plants increased by 20%. This technique allows the flower to attract other insects as soon as it has heard one, and thus effectively disseminate its pollen.

The team replicated the experiment by removing one or more petals: the flower no longer reacted to the buzzing. The flower petals would therefore act as ears. It is surely for this reason that many flowers have a parabolic antenna shape, ideal to receive and amplify the sound waves… even if for the moment this phenomenon has been identified only in a single species.

Evening primrose flowers © Getty / Whiteway

Is it really “ears”?

Let’s not go too far in the anthropomorphism – we speak of “ear”, but the plants do not have ears comparable to those of the animals. Instead, they have vibration detectors that are distributed throughout the cells of the body – and even in the roots, as seen with corn.

The discipline of phytoacoustics is today in full swing. Researchers must now understand the molecular or mechanical processes that are responsible for listening and processing sounds. Some scientists believe that plants could also be affected by the noises we emit.

Meanwhile, there is one that does not seem to complain: Desmodiym Gyrans, the plant that dances. We still have a hard time knowing why, but the sounds triggers to it some quick movements of its leaves, in rhythm please!

We suggest you to read this article about a plant which had not been breeding for over 60 million years but recently did!

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