Chili plants seem to be able to sense whether their neighbors are "good" or "bad"

Chili plants seem to be able to sense whether their neighbors are “good” or “bad” Image: Creative Commons Woodley Wonder Works

According to a new study published in BMC Ecology, plants can listen, smell, and see neighboring plants through acoustic signaling. In other words, plants hear vibrations and communicate using them. Study co-author Monica Gagliano says plants can tell whether a plant growing next to them is “good” or “bad,” which affects how well they grow.

“Plants are more complex organisms than we’ve given them credit for,” she says.

In the study, Gagliano and her partner observed chili plants grown in isolation versus those grown next to “good” plants that deter pests and weeds. The plants grown next to these “good” plants grew faster and healthier than those in isolation, even when they separated the plants using black plastic to prevent the exchange of chemical signals and light.

Last year, Gagliano conducted a similar experiment using “bad” neighboring plants such as fennel. Those results found that the chili plants could sense the presence of their growth-inhibiting neighbor, and that “seedlings allocated energy to their stem and root systems differently depending on the identity of the neighbor.”

Because the plants seem to still be able to sense the presence of other plants despite being partitioned off and chemical signals being blocked, Gagliano believes that they may be communicating using a universal “plant language” that involves vibrations.

“Whatever the signal is, we don’t know if the plants produce it for the purpose of signaling or if it is an accidental byproduct that other plants then ‘eavesdrop’ on,” said Gagliano’s colleage, Michael Renton.

This theory of plant communication is certainly still a young concept, and researchers recognize that. But they also agree that their findings thus far merit further research. Even if we can confirm that plants hear vibrations, much more research would be necessary before we are able to make good use of that knowledge. Gagliano hopes that someday we might make use of plant communication—such as using sound or vibration to encourage or discourage growth of certain plants.