However, it is distinguished by its slower, delayed repolarization phase, variability in shape and amplitude, and the decrease in its velocity with increasing distance from the initial point.
Depolarization arises from an increase in plant cell turgor pressure from a hydraulic pressure wave that moves through the xylem after events like rain, embolism, bending, local wounds, organ excision, and local burning.
Depolarization of a variation potential is determined by the difference in pressure between the atmosphere and the plant's intact interior.
However, it has been shown that variation potentials can be suppressed by high humidity and continued darkness.
This gradient transforms with distance into increasing lag phases for the pressure-induced depolarization in the epidermal cells.