SOURCE - SINK RELATIONSHIPS IN POTATO (SOLANUM-TUBEROSUM) AS INFLUENCED BY POTASSIUM-CHLORIDE OR POTASSIUM-SULFATE NUTRITION

In pot experiments with Solanum tuberosum L. (cv Saturna) the application of KCl as compared to K2SO4 delayed tuber development. The solute composition of leaves of the KCl treated plants was significantly lower in K+ and NO3-, but higher in Mg2+, Ca2+ and Cl-. Since the solute potential in the KCl treated plants was more negative and associated with a higher water content, a higher turgor pressure can be assumed. This could explain the enhanced shoot growth observed with KCl. Application of K2SO4, on the other hand, accelerated the development of tubers. This might result from a less competitive shoot sink in K2SO4 treated plants and a stimulated phloem loading and translocation of assimilates by higher concentrations of leaf-K. © 1990 Kluwer Academic Publishers.