When a tree experiences water stress, it does not remain silent. Studies led by Tel Aviv University in 2023 have shown that plants, such as tomatoes and grapevines, emit ultrasonic clicks at frequencies between 20 and 100 kilohertz, well above the human hearing range. These sounds, described as a dry, repetitive 'click,' increase dramatically in frequency when the plant undergoes severe dehydration, acting as a potential biological alarm signal.
The research, published in the journal Cell, used ultrasonic microphones to capture these sounds at distances of up to 5 meters. Surprisingly, the emission rate of these 'thirst clicks' can reach 30-50 times per hour under extreme drought conditions, whereas a well-watered plant barely produces a few per day. This discovery suggests that ecosystems could have an underestimated 'auditory channel,' where water stress is passively communicated through the air.
- Potential Application: Ultrasonic sensors could monitor crops in real time, allowing precision irrigation before leaves wilt.
- Key Fact: It is not a melodic 'singing,' but a physical mechanism caused by cavitation in the xylem, the vascular system that transports water.
This phenomenon redefines our understanding of plant life, showing that even the quietest organisms have ways to express their internal state. Plant sonification opens a new frontier in bioacoustics, with implications for sustainable agriculture and forest ecology.
Source: Research by Tel Aviv University published in the journal Cell (2023).
