Found via delhidailynews.com:
We already know that some plants can respond to sound. But the question which has aroused curiosity in everyone’s mind is that why would a plant develop the ability to hear. A new study has suggested that it is because they want to defend themselves against predators.
The whole thing is worth reading in full. Here’s another detail:
Some earlier studies on plants and sounds have found that in rice there are two genes which can switch on in response to music and clear tones. We also know that corn roots will lean toward vibrations of a specific frequency.
Access to the originating paper at the journal Oecologia (at springer.com). Here’s the abstract:
Plant germination and growth can be influenced by sound, but the ecological significance of these responses is unclear. We asked whether acoustic energy generated by the feeding of insect herbivores was detected by plants. We report that the vibrations caused by insect feeding can elicit chemical defenses. Arabidopsis thaliana (L.) rosettes pre-treated with the vibrations caused by caterpillar feeding had higher levels of glucosinolate and anthocyanin defenses when subsequently fed upon by Pieris rapae (L.) caterpillars than did untreated plants. The plants also discriminated between the vibrations caused by chewing and those caused by wind or insect song. Plants thus respond to herbivore-generated vibrations in a selective and ecologically meaningful way. A vibration signaling pathway would complement the known signaling pathways that rely on volatile, electrical, or phloem-borne signals. We suggest that vibration may represent a new long distance signaling mechanism in plant”“insect interactions that contributes to systemic induction of chemical defenses.