A note on blue light-induced potentials in Avena coleoptiles

Transverse electrical potentials were induced by 435.8 nm light, with lateral illumination of coleoptiles of Avena sativa L. cv. Blenda. The potentials were recorded with the aid of the vibrating electrode technique, thus avoiding touching of the plants. The light dose was varied by changing the illumination time, the irradiance always being 3.9.10^-3 W m^-2. The transverse potential varied in time after the start of illumination and the magnitude of it was dose-dependent. Maximum voltages recorded were of the order of 15 mV, the illuminated side of the coleoptile then being negative with respect to the shaded side. Dose response curves were constructed and were very similar to dose response curves published in the literature for phototropic (blue light induced) curvatures.