Effects of Electrical Currents on Desmodium gyrans Leaflet Movements – Experiments Using a Current Clamp Technique

Abstract

The leaflet rhythm of Desmodium gyrans, the period of which is in the minute range, was investigated by application of direct current pulses through the pulvinus. The current was generated in a current clamp device, and applied via a 0.1 mm copper wire electrode to the tip of the leaflet and to the base of the leaf stalk. Currents of 2, 5 or 10 µA were applied for 1 s, being kept at a constant value by the clamp electronics. The phase shift was in all cases a delay, attained after transients of four or five periods. The shifts were longer with increasing current. The electronic equipment developed to attain the current pulses is described.