Sodium and Potassium Uptake by Seedlings of Hordeum Vulgare

Abstract

Uptake of potassium and sodium from culture solutions by barley seedlings under a range of experimental conditions has been determined. It was shown that both sodium and potassium transport to the shoot was due to an active process in the root which was limited by the plant's growth. This process was not available for uptake of divalent cations. Sodium uptake at higher concentrations showed some relation to transpiration and the resulting increase in sodium uptake with concentration reduced the selectivity in the plant for potassium to sodium. It was shown that potassium transport across the root was independent of water flow to the cytoplasm. The role of the cytoplasm in selective ion uptake to the shoot is discussed.