It is also possible that other plants are eavesdropping. Several of the researchers previously found that plants boost the sugar levels in their nectar when they "hear" nearby pollinators. Meanwhile, other research has revealed that plants change their gene expression in response to sounds.
"If other plants have information about stress before it actually occurs, they could prepare," says Hadany.
"So now that we know that plants do emit sounds, the next question is—'who might be listening?'" says Hadany. "We are currently investigating the responses of other organisms, both animals and plants, to these sounds, and we're also exploring our ability to identify and interpret the sounds in completely natural environments."
https://www.treehugger.com/stressed-plants-make-sounds-we-cant-hear-7371983