Is this plant yelling? And, if so, what is it saying? Is this plant yelling? And, if so, what is it saying? Is this plant yelling? And, if so, what is it saying? (Photo: Alexei_other / Pixabay)

Scientists believe that plants scream when they’re stressed

One experiment showed a plant that let out a distress call when its stem was cut.

If a plant screams in the forest and nobody is there to hear it, did it actually scream?

The answer to that, it can now be determined, is a resounding yes. That's according to new research from Itzhak Khait of Tel Aviv University in Israel. Khait and his colleagues of plant communication experts placed microphones near tomato and tobacco plants. Were the plants gossiping with each other? Well, sort of. The microphones picked up ultrasonic sounds that could be heard by animals and insects – but not by the human ear, unless the humans were using high-end audio equipment. (Sorry, you won't be hearing any plant screams on Spotify anytime soon.)

Their study found something remarkable: A plant that's suffering from a drought can emit a sound, warning an animal like a moth that this particular plant is not the best place to lay an egg. It may even serve as a warning to other plants that there is an insufficient amount of water in the area. They apparently hear the "water stressed" screams of the plant. In another experiment, a plant let out a distress call after its stem was cut. "Our results suggest that animals, humans, and possibly even other plants could use sounds emitted by a plant to gain information about the plant’s condition," they wrote.

The authors point out that the behavior is actually in line with the natural order of things, considering that a plant's ability to sense its environment and respond to it is critical for its survival. So, it would seem, plants have some sort of consciousness. Charles Darwin was actually one of the first scientists to pose this notion, and his theories eventually led to a field known as plant neurobiology. Later research has found that plants can actually see, smell and hear. Japanese botanists used anesthesia on plants to see if they would "wake up" when the drugs wore off. They did.

Honeybee flying to pink Nemesia flower A honeybee flying to a pink Nemesia flower. (Photo: Sumikophoto / Shutterstock)

Plants have even been known to show some learning behavior. In a study done last year by the same team of zoologists and plant scientists in Israel, they found that flowers can actually hear the buzzing of bees. The plants hear bees approaching and attempt to lure them in with sweeter nectar. In several experiments, they found you didn't even need actual bees. They simply played audio recordings of buzzing bees around certain flowers. Those recordings caused the sugar concentration in the nectar to rise by about 20% in less than five minutes. Such a rapid reaction by plants to sound had never previously been reported.

Plants can even hear human voices. In a 2009 study, Britain's Royal Horticultural Society found that women's voices help make plants grow faster. In that experiment, tomato plants were found to grow up to two inches taller when they were tended to by a female gardener. "The findings vindicate comments made by Prince Charles that he talks to his plants, although they suggest that for maximum results he would be better off recruiting the Duchess of Cornwall," wrote The Telegraph at the time.

So the next time you're in the forest and think you're alone, think again. Those plants are listening – and may even be trying to talk to you.

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Scientists believe that plants scream when they’re stressed
One experiment showed a plant that let out a distress call when its stem was cut.