Arabidopsis trichomes (hair cells) respond to mechanical stimuli by initiating potential signaling factors in themselves and in the neighboring cells. These vibrational responses of Arabidopsis trichomes support the hypothesis that trichomes respond acoustically to vibrations associated with feeding caterpillars. Trichomes have vibrational modes in the frequency range of the sounds of feeding caterpillars, encouraging further experimentation to determine whether trichomes serve as mechanical antennae. Arabidopsis plants have been reported recently to react to the sounds of caterpillars of Pieris rapae chewing on its leaves by promoting synthesis of toxins that can deter herbivory. Identifying leaf trichomes as acoustic antennae of plant cells suggests potential “ears” of Arabidopsis.
https://www.sciencedirect.com/science/article/pii/S000634951730989X