Abstract
Theoretical back-ground and principle of electro-physiological method for the study of root physiology were reviewed. The applicability of a model of electro-physiological structure to the root system in the field was experimentally examined and discussed. A convenient system via a perfect liquid junction was developed for long term measurement of trans-root electric potential (TRP) in field trees. The electro-radicogram of a kaki tree (Diospyros kaki) showed a regular diurnal changes. The seasonal change in the potential level and in the amplitude of oscillation was observed, and discussed in relation to the root activity and the environment.
