A team of scientists has reported that tomato and tobacco plants emit ultrasonic popping sounds when dehydrated or physically damaged.
According to one report, ‘When deprived of water or snipped with scissors, plants emit a flurry of staccato ‘screams’ that are too high-frequency for humans to hear, a study suggests. When lowered into a range that human ears can detect, these stress-induced pops sound like someone furiously tap dancing across a field of bubble wrap.
‘Although humans cannot hear these ultrasonic pops without technological assistance, various mammals, insects and even other plants may be able to detect these noises in the wild and respond to them.’
“When these plants are in good shape, they produce less than one sound per hour, but when stressed they emit many more, sometimes 30 to 50 per hour,” said Prof Lilach Hadany, an evolutionary biologist and theoretician at Tel Aviv University. “They are potentially important because other organisms could have evolved to hear these sounds and interpret them,” she added. “We are now testing both animals and plants to see if they respond.”
Writing in in the scientific journal Cell, the researchers said the plants’ sounds are as loud as human speech and are emitted more frequently after two days without water. The pops peak at day five or six and then subside as the plant dries up.