We all know that plants don't have ears, but are they capable of hearing? A recent study shows that they have the ability to perceive sounds.
In addition to the discovery about the ability to "hear" of plants, it was also concluded that they can emit ultrasound. The flowers would be the ones that act as ears.
How was the experiment?
Lilach Hadany and Yossi Yovel Sands are the two scientists from Tel Avih University, responsible for the experiment that shows that some plants can hear sounds.
The researchers took 650 primrose flowers and analyzed their levels of nectar production. Then, they observed if they reacted to sounds of three different frequencies (high, medium and low), a recording of the buzzing of a bee and also to silence.
The flowers, when exposed to low sounds and those of the bees, produced 20% more nectar. Before the silence, there were no variations in production.
But how is it that plants capture sounds?
The scientists also wanted to see how the plants managed to capture sounds. For this they carried out the same test, but extracting the petals from the flowers. The results were negative, there was no increase in the production of nectar and thus they concluded that it was the flowers that acted as the "ears" of the plants.
The flower acts like the fleshy folds of the human outer ear, channeling sound to the plant.
Plants also make ultrasonic sounds
Regarding the noise emitted, the team of researchers placed tobacco and tomato plants inside soundproof boxes, in front of sensitive microphones that allowed their capture.
The experiment showed that the plants emitted short ultrasonic sounds, with a volume of sixty decibels, perceptible to moths and bats but not to humans. They are brief and tend to fade into the distance.
The team found that plants that are dry or damaged often make noise. The sounds vary with the type of damage or degree of dryness. In theory, animals could use sounds to obtain information about the condition of a plant.
In another study, Monica Gagliano, an evolutionary biologist at the University of Western Australia, and her colleagues deposited pea seedlings in inverted Y-shaped jars.
One of the arms of the bottle rested on a tray with water or a plastic screwed tube through which the element liquid circulated; the other rested on dry land.
The roots grew towards the arm of the water, whether it was easily accessible or circulated hidden by the tube. "They knew the water was there, although the only thing they could perceive was the noise as it passed through the pipe," he says. But when given the option to choose between the water tube and damp soil, the roots chose the latter. Gagliano hypothesizes that plants use sound waves to detect water in the distance but follow the humidity gradient to reach their goal when they are nearby.