Can plants hear?

Plants are organisms full of surprises - without a brain and central nervous system, they are still able to perceive the environment that surrounds them. They can sense light, smell, touch, wind, and even gravity and can respond to sounds.

No, music doesn't help plants grow—not even classical music—but other sound cues can help them survive and thrive in their habitats. Why is that so? Scientists Heidi Appel and Rex Cocroft from the University of Missouri were interested in whether plants would respond to the sound of insects eating, so they conducted several experiments.

First, they placed the caterpillars on Arabidopsis, a tiny flowering plant related to cabbage and mustard. Using a laser and a small piece of reflective material on a plant leaf, they were able to measure the movement of the leaf in response to the caterpillar's chewing. One group of Arabidopsis plants was then played recordings of the vibrations of the caterpillars they were eating, but the other group of plants was played only in silence. When the caterpillars were later fed on both groups of plants, the researchers found that the plants that had previously been exposed to the feeding vibrations produced more mustard oil,
a chemical that is not very attractive to caterpillars.

In a second experiment, the research team played a variety of recordings of Arabidopsis plants, including wind and a beetle's mating song, because it has a similar frequency spectrum to chewing, but a contrasting time pattern. The plants did not react to these vibrations at all. Remarkably, plants exposed to a variety of vibrations, including those emitted by a gentle wind or various insect sounds that share some acoustic properties with caterpillar feeding vibrations, did not increase their chemical defenses. This suggests that plants can distinguish feeding vibrations from other common sources of environmental vibrations. Caterpillars respond to this chemical defense by crawling away, so using vibrations to boost plant defenses could be very useful for agriculture.

In conclusion, we add that even though plants do not have heard, they perceive sound vibrations.

Source: https://www.calacademy.org/explore-science/do-plants-hear