title: Effect of adsorbed cations on phosphorus uptake by excised roots.
abstract: Pretreatment of excised roots of Hordeum vulgare, Zea mays, and Glycine max with various salt solutions affected their subsequent rate of phosphorus absorption from 2 x 10(-5)m KH(2)PO(4). The rate of absorption was greatest for roots pretreated with trivalent cations, intermediate with divalent cations and lowest with monovalent cations. It appeared that the pretreatment involved a rapid exchange reaction at the root surface which was reversible. A 1 min pretreatment was effective for more than 20 min. The acceleration of phosphorus uptake by roots produced by polyvalent cations may be due partly or entirely to a greater reduction in the electrical potential at the root surface or within the pores of the negatively charged cell wall by polyvalent cations than by monovalent cations.
authors.affiliation: Department of Agronomy, Ohio Agricultural Research and Development Center and Ohio State University, Columbus, Ohio 43210.
authors.forename: R E
authors.initials: RE
authors.lastname: Franklin