Are plants really the kinder dietary choice? A new report suggests they could ‘scream’ when being cut.
Researchers from Tel Aviv University, Israel, have suggested plants stressed by drought or physical damage may emit high-frequency distress noises.
As part of the experiment, they placed microphones near tomato and tobacco plants subjected to drought conditions and cut stems – the instruments picked up ultrasonic ‘screams’ within a range of 20 to 100 kilohertz from around 10 centimetres away.
This is a volume the scientists believe could be picked up by some animals – the authors speculated insects may listen for sounds emitted by plants to check their health before laying eggs on their leaves.
The researchers were able to use machine learning technology to sort plants into three categories depending on the noise they emitted – dry, cut or intact – and suggested this could be used in the future to check whether crops are suffering from drought conditions.
Researchers said: “Stressed plants show altered phenotypes, including changes in colour, smell, and shape. Yet, the possibility 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.”