Plant bioacoustics

Preliminary evidence supports that plants create sound in root tips when cell walls break.

Some 20000 plants species,[7] including Dodecatheon and Heliamphora have evolved buzz pollination in which they release pollen from anthers only when vibrated at a certain frequency created exclusively by bee flight muscles.

Oenothera drummondii (beach evening primrose) is a perennial subshrub native to the Southeastern United States, but has become naturalized on almost every continent.

It has been discovered that O. drummondii flowers produce significantly sweeter nectar within three minutes when exposed to bee wingbeats and artificial sounds containing similar frequencies.

[10] A possible mechanism behind this is the activation of mechanoreceptors by sound waves, which causes a flux of Ca2+ into the plant cell causing it to depolarize[11] Because of the specific frequencies produced by the pollinators’ wings, perhaps only a distinct amount of Ca2+ enters the cell, which would ultimately determine the plant hormones and expression of genes involved in the downstream effect.

Evidence for plant mechanosensory abilities are shown when roots are subjected to unidirectional 220 Hz sound and subsequently grow in the direction of the vibration source.

Furthermore, ultrasonic acoustic emissions (UAE) have been detected in a range of different plants which result from collapsing water columns under high tension.

Mechanical vibrations caused by charged cell membranes and walls is a leading hypothesis for acoustic emission generation.