The Effects of Infra-Red, Visible and Ultra-Violet Irradiation on Changes in Electrical Potentials and Currents in Plants

Abstract

Marked changes in difference of potential between the base and tip of leaves in intact plants are produced by ultra-violet and infra-red radiations. Little if any such change is produced by visible light. From various experiments outdoors it is concluded that these changes in electromotive force are due chiefly to infra-red radiations of sunlight. Indoors, marked differences of potential may be caused by exposing the leaf to gases drawn from the vicinity of quartz-mercury or other metallic arcs. When a constant electromotive force is impressed across the 2 electrodes, the values of the currents in the circuit are increased by either ultra-violet or infra-red radiation.