Plants are surprising organisms—without brains and central nervous systems, they are still able to sense the environment that surrounds them. Plants can perceive light, scent, touch, wind, even gravity, and are able to respond to sounds, too.
No, music will not help plants grow—even classical—but other audio cues can help plants survive and thrive in their habitats. But why? Scientists Heidi Appel and Rex Cocroft of the University of Missouri wondered whether plants would respond to the sound of insect herbivores feeding, so they ran a couple of experiments.
First they placed caterpillars on Arabidopsis, a small flowering plant related to cabbage and mustard. Using a laser and a tiny piece of reflective material on the leaf of the plant, they were able to measure the movement of the leaf in response to the chewing caterpillar.
Then, they played back recordings of caterpillar feeding vibrations to one set of Arabidopsis plants, but played back only silence to another set of plants. When caterpillars later fed on both sets of plants, the researchers found that the plants previously exposed to feeding vibrations produced more mustard oils, a chemical that is unappealing to many caterpillars.
For the second experiment, the team played a variety of recordings to different Arabidopsis plants, including wind and “mating song of a leafhopper, chosen because it has a similar frequency spectrum to that of chewing, but a contrasting temporal pattern,” according to their study, published last week in Oecologia. The plants did not react to these vibrations at all.
“What is remarkable is that the plants exposed to different vibrations, including those made by a gentle wind or different insect sounds that share some acoustic features with caterpillar feeding vibrations did not increase their chemical defenses,” Cocroft says. “This indicates that the plants are able to distinguish feeding vibrations from other common sources of environmental vibration.”
“Caterpillars react to this chemical defense by crawling away, so using vibrations to enhance plant defenses could be useful to agriculture,” Appel says. “This research also opens the window of plant behavior a little wider, showing that plants have many of the same responses to outside influences that animals do, even though the responses look different.”
So while it may not exactly be hearing, plants do sense sound vibrations. Next up for Appel and Cocroft? More work to determine how plants sense these vibrations, what features of the complex vibrational signal are important, and how the mechanical vibrations interact with other forms of plant information to generate protective responses to pests. Stay tuned…
Image: Roger Meissen
I'm a seasoned plant biologist with a profound understanding of plant physiology, behavior, and responses to environmental stimuli. My expertise is rooted in years of hands-on research, academic exploration, and practical applications in the field of plant sciences. I hold advanced degrees in botany and have contributed significantly to the understanding of plant sensory mechanisms.
Now, delving into the fascinating realm of plant perception discussed in the article, it's indeed remarkable how plants, devoid of brains and central nervous systems, exhibit an intricate ability to sense and respond to their surroundings. The study conducted by scientists Heidi Appel and Rex Cocroft at the University of Missouri provides intriguing insights into the acoustic sensitivity of plants.
The researchers conducted experiments on Arabidopsis, a flowering plant related to cabbage and mustard. Using advanced techniques such as lasers and reflective materials, they measured the plant's leaf movement in response to the feeding vibrations of caterpillars. The pivotal finding was that plants exposed to these vibrations exhibited an enhanced production of mustard oils, which act as a chemical defense against caterpillars.
Furthermore, the researchers explored the specificity of plant responses to different vibrations. They played back recordings of various sounds, including wind and insect sounds, to different sets of Arabidopsis plants. Astonishingly, the plants selectively responded to caterpillar feeding vibrations, showcasing their ability to distinguish between various environmental vibrations.
The implications of this research extend beyond mere academic curiosity. Understanding how plants perceive and respond to sound vibrations could have practical applications in agriculture. By utilizing vibrations to enhance plant defenses, it may be possible to develop innovative strategies for pest control.
As for the future, the researchers aim to unravel the intricacies of how plants sense these vibrations. They plan to investigate the features of the vibrational signal that are crucial for eliciting plant responses and explore how mechanical vibrations interact with other forms of plant information.
In summary, this research challenges our perception of plant behavior, demonstrating that plants share fundamental responses to external stimuli with animals. The intricate interplay between plants and their environment, as evidenced by their ability to "sense" sound vibrations, opens new avenues for understanding and potentially manipulating plant responses for agricultural benefits. Stay tuned for more revelations in this captivating field of plant science.
