Plant Sounds

[Nikita Desjardins]

Plantmusic is a way of monitoring electrical signals of plants as sound. Through patented sonification technology, PlantWave measures biological changes within plants, graphs them as a wave and translates the wave into pitch.

We use cookies to give you the best online experience and to show personalised content and marketing. We use them to improve our website and content as well as to tailor our digital advertising on third-party platforms. You can change your preferences at any time.

Professor Lilach Hadany, an evolutionary biologist at Tel Aviv University and author of the study, says, 'Even in a quiet field, there are actually sounds that we don't hear, and those sounds carry information.'

Healthy and stressed plants were recorded using microphones in a soundproof acoustic chamber and a noisier greenhouse. They were stressed using two methods, not watering them for several days and cutting their stems.

Water-stressed plants started emitting more rapid noises before visible signs of dehydration, such as the browning of leaves, began appearing. The sounds peaked after five days without water and dropped off as the plant dried up completely.

Interestingly, sounds were different depending on the cause of the stress. Researchers were able to train a machine-learning algorithm to accurately differentiate between unstressed plants, thirsty plants and cut plants. It could also tell which type of plant the sounds came from.

Dr Norbert Holstein, a botanist at the Museum who was not involved in the study, says, 'Many things emit sounds. For example, leaves rustling in the wind or the sounds a hungry tummy makes when the gut walls move against each other.'

Previous research has shown that plants can respond to sounds and vibrations created by pollinators, which triggers them to increase sugar concentration in their nectar. But if and how other plants or animals may respond to acoustic signals from plants is not fully understood.

'Now that we know that plants do emit sounds, the next question is - who might be listening?' says Lilach. 'It's possible that other organisms could have evolved to hear and respond to these sounds.'

'We are currently investigating the responses of other organisms, both animals and plants, to these sounds, and we're also exploring our ability to identify and interpret the sounds in completely natural environments.'

Receive email updates about our news, science, exhibitions, events, products, services and fundraising activities. We may occasionally include third-party content from our corporate partners and other museums. We will not share your personal details with these third parties. You must be over the age of 13. Privacy notice.

In an experiment, researchers denied water to some tomato and tobacco plants and cut the stems of others, then they placed microphones nearby. The devices picked up on noises coming from the plants that were outside the range humans can hear. However, researchers say other animals could theoretically detect the sounds from about 10 to 15 feet away, according to the paper.

But the sounds the plants made did hint at the specific types of stresses they were experiencing. A machine learning algorithm was able to distinguish between the sounds of a cut plant and the sounds of a dehydrated plant 70 percent of the time.

The scientists placed microphones about four inches away from the plants and found that the stressed crops made noises more frequently than their unstressed counterparts. Dehydrated tomato and tobacco plants emitted an average of about 35 and 11 sounds per hour, respectively. Cut tomato and tobacco plants made 25 and 15 noises per hour. Healthy plants, on the other hand, emitted far fewer sounds, at less than one per hour.

Are there any plants that are at least able to produce some sort of sound? Actively, I mean - depleting energy reserves to produce an audible output, preferably with no experimental amplification. Ultra- or infrasound is also ok.

Plants make noise all the time as they transport water but that is believed to be an unintentional by-effect. As to the possibility of plants intentionally making noise,my intuitive answer was no but I might well be wrong, there is actually increasing evidence that plants might produce vibrations for communication.

Two examples: Gagliano (2012) discovered that young maize roots subjected to a 220 Hz sound (check out the figure, not sure if I'm allowed to copy it here) grow towards the sound source and additionally emit periodic bursts of sound themselves for as of yet unclear reasons. Gagliano, Renton, et al. (2012) demonstrated that chili plant seedlings grow faster in the presence of an adult fennel plant even though this adult plant was isolated in a such a way that it could not communicate via any known mechanism (chemical, light) with the seedlings, indicating influence through an unknown mechanism. The authors consider both magnetism and sound as possible unknown communication methods.

...Note that mine were a lot bigger. After watering them and leaving them in the sun (enhances re-hydration by promoting water flow through evaporation of water through the leaves) you could literally see the leaves and stem erecting themselves again by the re-hydration process. If I remember correctly, some of those leaves would make audible sounds when they became dis-entangled from underlying leaves (popping sounds). They would look something like this after watering them.

The site is secure.

The ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Stressed plants show altered phenotypes, including changes in color, smell, and shape. Yet, airborne sounds emitted by stressed plants have not been investigated before. Here we show that stressed plants emit airborne sounds that can be recorded from a distance and classified. We recorded ultrasonic sounds emitted by tomato and tobacco plants inside an acoustic chamber, and in a greenhouse, while monitoring the plant's physiological parameters. We developed machine learning models that succeeded in identifying the condition of the plants, including dehydration level and injury, based solely on the emitted sounds. These informative sounds may also be detectable by other organisms. This work opens avenues for understanding plants and their interactions with the environment and may have significant impact on agriculture.

Similar to the popping of popcorn, they are emitted at a volume similar to human speech, but at high frequencies, beyond the hearing range of the human ear, according to the team from Tel Aviv University.

For the first stage of the study, published in the journal Cell, the researchers placed plants in an acoustic box in a quiet, isolated basement with no background noise. Ultrasonic microphones record sounds at higher frequencies than the maximum detectable by a human adult, which is about 16 kilohertz. Mics were set up at a distance of about 4 inches (10cm) from each plant, including tomatoes, grape vines, tobacco, wheat, corn, cactus, and henbit.

The recordings collected in this way were analyzed by specially developed machine learning (AI) algorithms. The algorithms learned how to distinguish between different plants and different types of sounds, and were ultimately able to identify the plant and determine the type and level of stress from the recordings.

Moreover, the algorithms identified and classified plant sounds even when the plants were placed in a greenhouse with a great deal of background noise. In the greenhouse, the researchers monitored plants subjected to a process of dehydration over time and found that the quantity of sounds they emitted increased up to a certain peak, and then diminished.

Here, we are in the world of assumptions. The study was able to show that plants make different sounds depending on the species and the nature of the stress (in this case, drought or cutting). However, some hypotheses make a lot of sense.

Also, plants may react to sound to protect themselves from drought. If a neighbor is short of water and we perceive his stress, we manage not to lose our own water unnecessarily and we slow down his transpiration (yes, plants breathe and transpire!).

I remember hearing about a tree that emitted pheromones when it was nibbled by an animal. It warned its neighbors, who sent a compound into their leaves to present an unpleasant taste and protect themselves. Maybe there is a similar influence with sounds?

The authors of the article would like to see this knowledge used one day, for example to understand plants in the field or in greenhouses in order to increase productivity, or to identify stress early on. They discovered that the plant emits sounds faster and faster depending on the intensity of the stress. Why wait for our plant to get low? As soon as it makes sounds, hop! A little water!

"Even in a quiet field, there are actually sounds that we don't hear, and those sounds carry information," says senior author Lilach Hadany, an evolutionary biologist and theoretician at Tel Aviv University. "There are animals that can hear these sounds, so there is the possibility that a lot of acoustic interaction is occurring."

Although ultrasonic vibrations have been recorded from plants before, this is the first evidence that they are airborne, a fact that makes them more relevant for other organisms in the environment. "Plants interact with insects and other animals all the time, and many of these organisms use sound for communication, so it would be very suboptimal for plants to not use sound at all," says Hadany.

The researchers used microphones to record healthy and stressed tomato and tobacco plants, first in a soundproofed acoustic chamber and then in a noisier greenhouse environment. They stressed the plants via two methods: by not watering them for several days and by cutting their stems. After recording the plants, the researchers trained a machine-learning algorithm to differentiate between unstressed plants, thirsty plants, and cut plants.

3a8082e126