Plant bioacoustics: decoding ultrasonic emissions

For decades, plant-environment interactions were understood to be primarily mediated by chemical and visual stimuli. However, recent evidence has unveiled an underexplored dimension of plant physiology: airborne ultrasonic emissions. This review evaluates current research in plant bioacoustics, focusing on ultrasound generation, characteristic features, and specificity across different stress conditions. We discuss proposed mechanisms for plant ultrasound production, with a primary emphasis on xylem cavitation. Advancements in non-contact monitoring have enabled the characterization of acoustic phenotypes which can be employed to determine plant water status. Furthermore, we synthesize the potential molecular, ecological, and technological implications of ultrasonic emissions. While the possibility for inter-organismal communication remains a subject of intense debate, specifically regarding whether the ultrasounds represent evolved signals or merely incidental physiological cues, the ability to classify ultrasounds using machine learning algorithms offers transformative opportunities for precision agriculture, ecosystems monitoring, and a more comprehensive understanding of plant-environment dynamics.