title: Accumulation of potassium and sodium by barley roots in a k-na replacement series.
abstract: Excised roots of barley (Hordeum vulgare, var. Campana) were incubated for 24 hr in solutions containing constant total concentrations of KCl and NaCl but in which the mole fractions of K and Na were varied in replacement series. In solutions containing 1, 10, or 50 mm concentrations of K(+) plus Na(+), total cation accumulation was dependent upon the total salt concentration but was relatively independent of the mole fractions of K(+) and Na(+). These results imply that accumulation of K(+) and Na(+) was limited by a common factor. In solutions containing 0.01 mm K(+) plus Na(+) there was a strong preference for K(+) over Na(+) and the sum of K(+) and Na(+) accumulation increased with increasing K(+) concentration.In the replacement series utilizing 0.1 mm K(+) plus Na(+), K(+) accumulation reached a peak at solution concentrations of 0.04 mm K(+) and 0.06 mm Na(+). Potassium accumulation then decreased as Na(+) was further replaced by K(+) to concentrations of 0.06 mm K(+) and 0.04 mm Na(+). Potassium accumulation again increased with additional replacement of Na(+) by K(+).
authors.affiliation: Department of Agronomy, University of Kentucky, Lexington, Kentucky 40506.
authors.forename: A J
authors.initials: AJ
authors.lastname: Hiatt