Note on the Effect of Unilateral Illumination on the Transverse Electrical Polarity in the Avena Coleoptile.

Introduction The effect of incandescent light on the electrical potentials of etiolated seedlings has been studied by only a few investigators. WALTm E(7) maintained that etiolated seedlings gave little, if any, electrical response when illuminated. CLARK (1), however, has demonstrated changes in the longitudinal electrical polarity in intact etiolated Avena seedlings when they are uniformly illuminated by 600,000 meter-candle-seconds. Isolated Avena coleoptile sheaths when illuminated manifest electrical polarity changes similar to the intact plants (5). Previous experiments have shown that transverse electrical polarities with the same orientation with respect to subsequent curvature are established in the Avena coleoptile by gravity (6) and mechanical stimulation (3, 4). The present experiments show the effect of unilateral illumination on the transverse electrical polarity in the apical region of the isolated coleoptile sheath. Materials and methods