Researchers from the AGH University of Science and Technology in Kraków and the Department of Horticulture at the Wrocław University of Environmental and Life Sciences are investigating whether plants emit sounds, inaudible to the human ear, in response to stress factors such as water deficiency, excessive drying, or pest attacks.
These sounds may indicate that the plants are in distress. The collaboration between the Advanced Horticultural Production Technology Center at UPWr and Kraków's AGH has resulted in studies that could be useful in plant diagnostics. The data and conclusions from ongoing experiments may offer growers insights on how to better care for large-scale crops and respond more quickly to changes related to irrigation or pest protection.
Dr. Janusz Mazurek from the Department of Horticulture at UPWr acknowledges the practical significance of studying the sounds produced by plants: " We consider these types of studies innovative, and the results can help us in researching plant stress caused by physiological factors such as water shortage, excessive temperature, or nutrient deficiency, as well as those caused by diseases and pests. In horticultural production, quick, and in this case non-invasive, problem detection determines the effectiveness of the producers' actions. This aligns with integrated production practices," explains the UPWr scientist.
The sounds emitted by plants are at frequencies beyond the range of human hearing. The ultrasonic sounds can only be recorded using specialized microphones, which are regularly used by scientists in the Acoustic Engineering Laboratory at the AGH Faculty of Mechanical Engineering and Robotics in Kraków.
"The first stage of the research was conducted in the experimental greenhouse at the Center for Innovative Technologies at the Wrocław University of Environmental and Life Sciences, where we studied young tomato seedlings, which grow quickly under optimal conditions. It was important for us to ensure the best possible growing conditions, which only the skilled staff working daily in the experimental greenhouses could provide. The growth rate of the tomatoes during our measurements reached up to 30 cm per week," explains AGH PhD student Klara Chojnacka, detailing the initial research stage.
Measurements in the greenhouse revealed that the plants did indeed emit ultrasonic pulses, and their frequency varied depending on the time of day. More pulses were generated during the day, she adds.
The sounds produced by plants are known as impulse noise, which, as explained by the team of acousticians from AGH, is easy to distinguish from constant noise generated by lighting, equipment, or people. The results from the greenhouse measurements in Wrocław confirm earlier, limited studies on plants (research results on plant sounds were published by a team from Tel Aviv University).
Read more on UPWR.edu.