Do Plants Hear? (Understanding Plant Hearing)
The survival of living beings depends on their ability to sense their environment. While plants sense the world much differently than use, they too have developed sophisticated means to interpret their surroundings. But do plants hear their surroundings?
Plants don’t have external or internal ears but they can still hear. They use the sound vibrations in the air or soil to sense their surroundings. Scientific research suggests that plants can hear for example running water, pests, pollinators, and possibly even other plants.
While the sense of hearing may not seem useful to plants, it serves an incredibly important role in their biology. Sound travels fast, far, through various mediums, and is difficult to obstruct, giving those who sense it a competitive edge. While the understanding of these mechanisms is only in its scientific infancy, research has shown that plants are listening more than we would have ever thought.
This has led to the development of an entirely new branch of science known as “phytoacoustics”, the science of plant hearing.
In this article, you’ll learn how plants hear their surroundings. You’ll learn about the scientific experiments that were done to better understand plant hear and what the effects of music can be.
Plant Hearing
As I already mentioned, plants don’t have external or internal ears. But this doesn’t mean that they are incapable of “hearing”. Plants hear through the vibrations that sound makes. All sound is nothing more than a vibration through a certain medium, like air or soil.
Plants will use their hearing to find water and nutrients but also to defend themselves against potential predators.
Plants can hear running water
Plant roots in urbanized areas often cause plumbing issues as they strangle water pipes and start to grow withing them. But why does this happen?
Researchers from the University of Western Australia discovered that plants grow towards the sound of running water inside the piping. They observed how roots in soil grew towards perfectly sealed tubes of running water, even without a temperature or moisture gradient.
Plant roots even had a greater tendency to grow towards artificial recordings of running water. When exposed to both a moisture gradient and the sounds of running water coming from the opposite direction, plant roots grow towards the moisture gradient.
This suggested to the researchers that plants may use sounds to detect water from a distance when moisture gradients are not present.
Plants can hear noxious pests
Plants are not only capable of hearing water, but plants also seem to be able to use the sound produced by their predators to sense their pests and up their defenses.
Researchers from the University of Missouri showed that plants can sense the sounds emitted by caterpillars as they chew on their foliage. In response to these sounds, plants will begin to produce defense compounds in larger quantities as a means to repel the pest.
Researchers showed this by recording the sounds of leaf chewing by caterpillars and replaying the sound to unpredated plants. It turned out that plants were not only listening but were able to identify these distinct vibrations from other sounds (like wind and rain) and develop a defense reaction in response. This allows for an important “priming” process, which prepares the plant for the attack before it happens.
Plants can hear their symbiotic pollinators
Pollinators are essential for the survival of most flowering plant species. They have driven the evolutionary development of elegant flowers, fragrant aromas, and sweet nutrient-rich nectar in plants. It turns out that these attractive and seductive structures are more sophisticated than they appear to the naked eye.
Researchers from Tel Aviv University discovered that flowers of some plants listen and recognize the sounds emitted by their pollinators, which in response increases the sugar concentration in their nectar. They showed this by playing the artificial sound of a bee’s buzz to their flowering plants. After only 3 minutes of these recordings, their flowers began to produce sweeter nectar.
Researchers suggested that producing sweeter nectar when there is an increased chance of pollination is beneficial to the plant in many ways. It ensures that this nutrient-rich nectar will not go to waste from spoilage or be robbed by a non-pollinating insect.
Sweeter nectar will ensure the pollinator does a more thorough job at pollination and increases the likelihood it visits a flower of the same species.
So the research suggests that the plant was able to detect these frequencies through the resonance of the flower petal with the specific frequencies emitted by the pollinators, in other words, hear its pollinators.
Plants and Music
One of the oldest legends in the plant word resolves around gardeners playing music to their plants to improve their health and to stimulate growth. But is this just a myth or is there science backing these legends?
Do plants like music?
There are specific musical albums (most notably “Mother Earth’s Plantasia”, but a google search results in thousands of hours of plant music) that were developed with plants intended as the main audience for the music.
If you’ve never heard of “plant music”, you should definitely listen to the music below:
While playing music to plants may sound like a fairy tale, research is showing that music actually can stimulate growth in plants.
Researchers played a wide variety of musical genres to plants of marigold and noticed increased growth and flower production when compared to those who remained unexposed. Secondly, plants exposed to noise in the form of non-rhythmic frequencies experienced detrimental effects.
So, there seems to be scientific evidence that plants do “like” music or at least like rhythmic frequencies.
Why do plants like music?
Plants have been shown to react positively to music but plants show a positive response to the non-musical sound of specific frequencies as well.
Researchers noted this and even observed that the most positive impacts occurred when the specific wavelengths of sound matched the dimensions of the leaf and promoted resonance. They hypothesized that these frequencies increased the ability and functioning of RNA to transcribe proteins and thus these wavelengths promote better growth. It is believed that plants enjoy music because of this same phenomenon.
Can Plants Hear Other Plants?
While it might seem even more far-fetched than plants liking music, some researchers are suggesting that plants may be listening to each other and communicating through the use of sound.
Plants are known to communicate through chemical signals both in the soil and the air. It is well known that plants may alarm each other (purposefully or not) of potential environmental threats like drought or herbivory. This allows plants to prepare themselves for these stresses before they occur.
Researchers argue that if plants can communicate through chemicals, there is no reason they might not communicate through sound. Plants are known to produce sound. Plants emit sound waves at 10–240 Hz as well as ultrasonic acoustic emissions ranging from 20 to 300kHz. These frequencies are likely altered by specific physiological states of the plants.
Want to Learn More?
If you want to learn more interesting facts about plants, you should definitely read the following articles:
- Are plants producers?
- Can plants get cancer?
