Retranslocation of Potassium in Beta vulgaris L. Under Conditions of Low Sodium Supply

Abstract

Potassium retranslocation was studied in B. vulgaris by sequential harvests of plants following transfer to a potassium-deficient medium. Absolute amounts of potassium in each blade and petiole and in other plant parts were calculated. There was a net retranslocation of 37.5% of the plant potassium in the 15 days following potassium cutoff. Blades and fibrous roots exported potassium readily, but petioles and beet tissue accumulated potassium even as the degree of deficiency increased. The eight oldest leaves (blade plus petiole) exported potassium throughout while the potassium in leaf 9 was relatively unchanged. Younger leaves were net importers of potassium. It is suggested that the redistribution is of survival value under conditions of potassium stress.