Sodium and Potassium Influx into Citrus Leaf Slices

Abstract

The influxes of sodium and potassium have been measured in slices of mature citrus leaves, using 22Na and 42K as tracers. External concentrations were 0·03-100 mM (sodium) and 0·I-100 mM (potassium). The sodium influx was always less than the potassium influx, for any given external concentration. In neither case was the influx increased by light. There was no effect on the influxes when chloride ions in the experimental solutions were replaced by sulphate ions.