The Relationship between the Cell Electrical Potential Difference and Salt Uptake in the Roots of Helianthus annuus

The effect of ringing the stem on the electrical potential difference(PD) in the root cortical cells of H. annuus was studied. PDand salt transport were followed simultaneously. By ringingit was possible to separate the PD from K⁺, , and Cl^– uptake and H⁺ efflux. The uptake of phosphatehowever was found to be closely connected with a component ofthe PD. It was concluded that there is an electrogenic pumpfor phosphate in these roots which generates 60–80 mV.