Researches recorded tomato and tobacco plants from ten centimeters away
They cut the stems of some plants and deprived others of water for several days
They found plans emitted as much as 35 distress sounds per hour in response
Normal plants produce less than one ultrasonic sound per hour
A team of scientists at Tel Aviv University have discovered that some plants emit a high frequency distress sound when they undergo environmental stress.
The researchers tested tomato plants and tobacco plants by depriving them of water and by cutting their stems and then recording their response with a microphone placed ten centimeters away.
In both cases, they found the plants began to emit ultrasonic sounds between 20 and 100 kilohertz, which they believed could convey their distress to other plants and organisms in the immediate vicinity.
When a tomato plant’s stem was cut, the researchers found it emitted 25 ultrasonic distress sounds over the course of an hour, according to Live Science.
Tobacco plants sent out 15 distress sounds when their stems were cut.
When the researchers deprived each plant of water, the tomato plants emitted even more distress sounds, 35 in one hour, while the tobacco plants made 11.
The plants also seemed to respond with different intensities of sound to different sources of stress.
The team observed that tobacco plants let out a louder sound when they were deprived of water than when they had their stems cut.
Plants that had no immediate environmental threat or damage, released less than one ultrasonic sounds per hour.