Ever gone on vacation and forgot to ask someone to water the plants? They might just be screaming for water when you return â€“ literally, screaming, in a register that you, as a human, simply canâ€™t hear. This might sound like science fiction, but according to new evidence, itâ€™s actually science fact.
In a recent study, researcher Itzhak Khait and his colleagues at Tel Aviv University in Israel found plants had senses like animals and humans and even utter ultra-sonic sounds when harmed, or in need of water.
â€œWe found that plants emit sounds, and that both drought-stressed plants and cut plants emit significantly more sounds than plants of any of the control groups,â€ their report claimed. The study has not been peer reviewed, but demonstrates some unique data.
The research team recorded sounds with two directional microphones pointed at each plant inside an acoustic box. The microphones were placed about four inches away from the plants inside the box. Researchers say the high frequency was such that animals like mice and moths would have been able to hear the sounds from several feet away.
According to a story in Newsweek, previous research has shown plants respond to stress by producing several visual, chemical and tactile clues. For example, stressed plants may differ in color and shape compared to unstressed plants. Meanwhile, some are also known to emit substances known as volatile organic compounds (VOC) in response to drought or being eaten.
A breakthrough like this could have far reaching benefits. By listening to food crops for example, farmers may â€œopen a new direction in the field of precision agriculture,â€ the team pointed out.
The researchers arenâ€™t sure how plants produce these sounds yet, but Khait and his colleagues propose one possibility in their paper: As water travels through the plantsâ€™ xylem tubes, which allow them to stay hydrated, air bubbles will form and explode, generating small vibrations. Previous studies have picked up these waves, but only through devices attached directly to the plants.