Plants may not have the sensory organs of humans, but they too can get stressed and audibly express that in a scream.
That's according to researchers at Tel Aviv University, who published their work on the peer review server bioRxiv. Led by Itzhak Khait, a plant scientist at Tel Aviv University, the researchers placed microphones that could detect ultrasonic frequencies, within inches of tomato and tobacco plants.
Plants emitted more sounds when starved of water, subjected to snippings
Some of the plants were starved of water while others got their stems snipped off. While the plants made occasional sounds when times were good, the tobacco plants that got their stems cut off, released around 15 sounds within an hour of the assault. The tomato plant was even more stressed, emitting 25 sounds within that period.
The tobacco plants that didn't get water for ten days, emitted 11 sounds within the hour while its seeming more sensitive tomato plant counterpart made 35 sounds.
The researchers then took the sound recordings and analyzed them via a learning model that can determine if the plants were making sounds because of the dryness or physical harm or if it was just daily chitchat. The one pattern that reportedly did emerge was that the tobacco plants that were thirsty made more noise than those that were snipped.
Understanding plants better can have a big impact on agriculture
"Stressed plants show altered phenotypes, including changes in color, smell, and shape. Yet, the 30 possibilities that plants emit airborne sounds when stressed – similarly to many animals – has not been investigated. Here we show, to our knowledge for the first time, that stressed plants emit airborne sounds that can be recorded remotely, both in acoustic chambers and in greenhouses," wrote the researchers in the paper.
The researchers said their work suggests animals, humans and maybe even other plants, can use the sounds coming from plants to get a sense of their conditions. For instance, their work can pave the way to create ways to better understand plants and how they interact with the environment. It could also have a big impact on agriculture if the plants screams signal more water is needed.