Spontaneous rapid leaf movements and action potentials in Mimosa pudica L

Movements and action potentials of Mimosa pudica L. plants, commonly known for their sensitivity to touch, were measured using time-lapse photography and extracellular electrical potential recording methods in 4-day experiments. In intact plants, spontaneous rapid leaf movements (RLMs) were revealed. The rapid downward movement of the leaf lasted approx. 1 s and the return to the previous position took approx. 17 min. Additionally, spontaneous action potentials (SAPs) with amplitudes of 3-100 mV and half-time of approx. 15 s were observed for the first time in M. pudica. Spontaneous APs propagated basipetally or acropetally with a velocity of 3-75 cm min^-1 . 36% of SAPs passing along the shoots were accompanied by RLMs. There was a delay between the appearance of SAP and RLM, indicating that SAPs may trigger the RLMs.