Plants heard making 'screaming' sounds for the first time ever

Have you ever talked or sang to a plant or a tree? Or maybe walked through a garden and wondered if the flowers were trying to tell you something? Fascinating new research suggests that plants seem to be emitting sounds and engaging in unheard conversations, especially when they’re stressed.

Lilach Hadany, an evolutionary biologist and theoretician, led a team that uncovered this surprising phenomenon.

They found that plants like tomatoes and tobacco emit sounds when they’re stressed, such as when they’re dehydrated or their stems are cut.

“Even in a quiet field, there are actually sounds that we don’t hear, and those sounds carry information,” says Hadany.

“There are animals that can hear these sounds, so there is the possibility that a lot of acoustic interaction is occurring.”

Plants emit sounds when they’re stressed

Using sensitive microphones, the researchers at Tel Aviv University recorded these plants in both soundproof chambers and noisier greenhouses.

They discovered that stressed plants emit sounds resembling pops or clicks — imagine the sound of bubble wrap being popped.

In fact, a single stressed plant can produce about 30 to 50 of these clicks every hour.

“When tomatoes are not stressed at all, they are very quiet,” Hadany notes. What’s fascinating is that these sounds are at frequencies too high for human ears to detect.

However, they are comparable in volume to normal human conversation and could potentially be heard by insects, mammals, and perhaps even other plants.

How to hear sounds from plants

To delve deeper, the team trained a machine-learning algorithm to differentiate between the sounds of unstressed plants, thirsty plants, and those that had been cut.

They found that not only do stressed plants emit more sounds, but the types of sounds also vary depending on the kind of stress.

Water-deprived plants began making noises even before showing visible signs of dehydration.

The frequency of their sounds peaked after five days without water and then decreased as the plants dried up completely.

Is there a universal plant language?

While the study focused on tomatoes and tobacco due to their ease of cultivation, the team didn’t stop there.

“We found that many plants — corn, wheat, grape, and cactus plants, for example — emit sounds when they are stressed,” says Hadany.

This raises the possibility that emitting sounds under stress might be a common trait among plants.

How does this happen?

The exact reason plants produce these noises is still a mystery. One theory is that the sounds result from cavitation — the formation and bursting of air bubbles in the plant’s vascular system.

But are plants intentionally communicating with these sounds?

“It’s possible that other organisms could have evolved to hear and respond to these sounds,” Hadany suggests.

“For example, a moth that intends to lay eggs on a plant or an animal that intends to eat a plant could use the sounds to help guide their decision.”

Implications for the natural world

If insects or other animals can detect these sounds, it could have significant ecological implications. Other plants might also be listening in.

“If other plants have information about stress before it actually occurs, they could prepare,” says Hadany.

Previous studies have shown that plants can respond to sounds and vibrations. For instance, some plants increase the sugar concentration in their nectar when they “hear” the buzz of pollinators.

Yossi Yovel, a neuro-ecologist at Tel Aviv University and co-senior author of the study, is excited about the potential applications of this discovery.

“We know that there’s a lot of ultrasound out there — every time you use a microphone, you find that a lot of stuff produces sounds that we humans cannot hear — but the fact that plants are making these sounds opens a whole new avenue of opportunities for communication, eavesdropping, and exploitation of these sounds,” Yovel explains.

Understanding these plant sounds could revolutionize how we approach agriculture. Farmers might one day use sound recordings to monitor crop hydration and stress levels, leading to more efficient water use.

Next steps in plant sound research

“So now that we know that plants do emit sounds, the next question is — ‘who might be listening?'” says Hadany.

“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,” Hadany concluded.

To sum it all up, by discovering that stressed plants emit sounds, researchers like Lilach Hadany and Yossi Yovel have unveiled a hidden layer of communication in nature.

These ultrasonic clicks and pops, though inaudible to us, could be influencing how insects, animals, and even other plants interact with their environment.

This finding change our understanding of plant behavior while opening practical applications in agriculture.

By listening to these silent signals, farmers could monitor crop stress levels and optimize watering, leading to more efficient farming practices.

As we continue to explore this unseen world of plant acoustics, we’re reminded of how much there is still to learn about the silent conversations happening all around us.

The full study was published in the journal Cell.

Video Credit: Tel-Aviv University

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