– Plants make sounds, but they are too high in pitch for us humans to hear.
– We can use these noises to tell if a plant is feeling stressed because they hold information about their condition.
– Researchers studied several different plants including tomatoes, tobaccos, wheat, corn, cactus and henbit.
– The researchers said that even though we can’t hear it, apparently meadows can be quite noisy!
Researchers at Tel Aviv University have made an amazing discovery. For the first time, they recorded and analyzed sounds coming from plants. It sounded like popcorn popping but it was too high-pitched for humans to hear. They found that when a plant is stressed out, it gives off very specific sound signals that can be heard by some animals such as bats, mice and insects. This is a groundbreaking global breakthrough!
Prof. Lilach Hadany, from the School of Plant Sciences and Food Security at the Wise Faculty of Life Sciences, lead a study with Prof. Yossi Yovel (Head of the Sagol School of Neuroscience), Itzhak Khait, Ohad Lewin-Epstein, and other researchers from Tel Aviv University. The results were published in Cell, which is an important scientific journal.
Professor Hadany explained: “Scientists have been wondering for a long time if the little vibrations that plants create can change into sound waves which can be heard from far away. Our research tried to answer this interesting question.”
The researchers conducted the study in a very quiet room with no noise. Ultrasonic microphones were placed about 10cm away from the plants, which recorded sounds in a very high range – between 20 and 250 kilohertz. This range is too high for people to hear, as humans can only detect up to 16 kilohertz. The experiment mainly focused on tomato and tobacco plants, but wheat, corn, cactus and henbit were also monitored.
Professor Hadany said that they tested some plants by putting them in an acoustic box. Some weren’t watered for five days, some had their stem cut, and others were totally untouched. This was done to see if the plants make any sound, and if the sounds change because of the conditions of the plants. The recordings showed that the plants made sounds between 40 and 80 kilohertz. Normally, unstressed plants only made less than one sound per hour but when stressed or dehydrated and injured, they made dozens of sounds every hour.
Researchers used special algorithms to process recordings of different plants and their sounds to figure out which plant it is and the level of stress that it’s experiencing. Even when there was a lot of noise in the background, the algorithms were still able to make these determinations correctly. These researchers put some plants in a greenhouse and found that as dehydration increased, the amount of sound that the plants produced gradually increased before reaching a peak maximum, then decreased again.
Professor Hadany explained in his study that plants do make sounds. These sounds share information like if they need water or are hurt. Apparently, nature is a lot more noisy than we think! It’s just that noise exists in frequencies too high for us to hear them. Animals like bats, rodents and insects can hear those noises but no worry, we can use special sensors to tell farmers when their plants need watering. So the world around us is definitely a lot more noisy than it looks!
Scientists want to find out more information about plants and the sounds they make. They want to discover how moths recognize these plant sounds and what is happening when the noise is made. Also, they are interested in exploring if other plants give off similar noises.
Plants can emit sounds when they are under stressful situations. Scientists have discovered that these sounds travel through the air and are carrying important information. A study published in the journal Cell on March 30th, 2023 by scientists Itzhak Khai, Ohad Lewin-Epstein and others found this to be true.
