Bioelectrical response of the Nitella flexilis cell to illumination: A new possible state of plasmalemma in a plant cell

Transient hyperpolarization of the external cytoplasmatic membrane may be observed on rapid illumination of the Nitella flexilis cell. Several important properties of that response make the latter similar to a considerable degree to the excitation response.The condition for transient hyperpolarization is the normal functioning of the electron transport chain conjugated with non-cyclic photophosphorylation.The value of the membrane potential at the moment of hyperpolarization of the external cytoplasmic membrane, is determined by the difference in the electrochemical potential of HCO₃^? or H⁺. This state of the plasmalemma supplements the two other known states: normal and depolarized (excited), when the main ions determining membrane potential are K⁺ and Cl^?.