Mechanosensation in leaf veins.

Whether the plant vasculature has the capacity to sense touch is unknown. We developed a quantitative assay to investigate touch-response electrical signals in the leaves and veins of . Mechanostimulated electrical signaling in leaves displayed strong diel regulation. Signals of full amplitude could be generated by repeated stimulation at the same site after approximately 90 minutes. However, the signals showed intermediate amplitudes when repeatedly stimulated in shorter timeframes. Using intracellular electrodes, we detected touch-response membrane depolarizations in the phloem. On the basis of this, we mutated multiple () genes expressed in companion cells. We found that double mutants attenuated touch-responses, and this was coupled to growth rate reduction. Moreover, propagating membrane depolarizations could be triggered by mechanostimulating the exposed primary vasculature of wild-type plants but not of mutants. Primary veins have autonomous mechanosensory properties which depend on P-type proton pumps.