Plants can emit and react to sounds.
In news to gladden the heart of Prince Charles, who was once mocked for admitting to talking to plants, it appears science has caught up with what many gardeners have long held true: plants can communicate by sound.
From an evolutionary stance, the reception and emission of sound is advantageous because it allows for the gain of information about the environment. Most organisms have evolved a diversity of sensory organs, both internal and external, to perceive sound. And although plants have no known auditory system, Dr Monica Gagliano, postdoctoral research fellow at the University of Western Australia, believes that the reception and transduction of sound does not necessarily require conventional auditory pathways. “These structures [auditory systems] are just one possible solution, but by no means constitute an essential requirement for hearing,” Gagliano says.
Gagliano and fellow researchers tested her theory on baby corn roots. They chose corn because it is easy to grow and only has a single root in its early stages, which simplified the experiment. Sound waves travel much louder and clearer in a dense medium such as soil and, therefore, experimenting on the plant root was ideal. “We figured the roots would be a good place to start. If it was going to happen, it was going to happen there,” Gagliano explains.
To test whether plants emitted or responded to sound, researchers used a microscanning laser Doppler vibrometer, a type of optical interferometer that measures velocity and is similar to the concept behind the Doppler effect. They found that the young corn roots generated frequent clicking noises at around 220 Hz. By suspending the roots in water, researchers also found that the roots noticeably leaned towards a continuous sound emitted in a similar region of 220 Hz.
Although researchers have only experimented using corn, Gagliano suspects that different plants may have different sound frequencies. “Eventually, we would like to expand our research to include as many species as we can to possibly create a library of data.”
Gagliano’s researcher will help us further expand our understanding of the sensory responses of plants, since, as the researcher suggests, “it is very likely that some form of sensitivity to sound and vibrations plays an important role in the life of plants.”
Source: University of Western Australia