Electrophysiological evidence for the permeability of white clover stolons to nutrient ions

Abstract

Membrane electrical potential differences (PD) of cells of white clover stolons and roots with secondary thickening have been measured. In dilute nutrient solution the PDs were ca — 154 mV for the 2nd and 10th internodes from the stolon tip and ca — 135 mV for buried internodes and thickened roots. PD between cells along the same radius did not differ consistently. Increasing the potassium concentration of the nutrient solution caused a rapid polarisation of the PD. Phosphate-free media caused the PDs recorded to be less stable and a number of the values to be less polarised. These results suggest that the cuticle and phellem in stolons do not prevent the entry of potassium and phosphate ions.