[Changes in vectors of endogenously generated ion currents in light-induced germination of turions of Spirodela polyrrhiza].

Nondormant turions of Spirodela polyrhiza (L.) Schleiden were utilized to investigate endogenous ion currents in light-induced germination and early growing processes of higher plants. A small outward current was detected at the ventral side of the turions near the pocket containing the most developed sprout primordium. After a light pulse, the direction of the endogenous current changed from outward to inward. These ion currents are most likely conditioned by unspecific diffusion of cations (probably H+) inside the cell. Three-day-old sprouts of Spirodela showed the highest inward current near the sprout base which decreases toward its edge. Newly formed sprouts demonstrated a strong gravity effect (bending), which was preceded by a lowering of the Z-component of vectors close to the sprout base after a change of the turion fixation.