Bioelectric Oscillations of Bean Roots: Further Evidence foraFeedback Oscillator III. Excitation and inhibition of Oscillations by Osmotic Pressure, Auxins, and Antiauxins

Abstract

After bean roots have been subjected to prolonged application of oscillations in osmotic pressure or ,8-indolylacetic acid (IAA) at the natural period, they exhibit an increased tendency for oscillatory behaviour. The amplitude of transient oscil-lations, reSUlting from sudden changes in osmotic pressure or in IAA concentration, is increased and the damping is decreased. In addition, the application of oscil-lations in osmotic pressure or in IAA of period considerably different from the plant's natural period, tends to evoke oscillations of the plant's natural period as well as those of the applied period. These effects are greatest at the root's elongating zone and have been interpreted in terms of an increase in the gain of a physio-logical feedback system responsible for oscillations in potential.