Simultaneous Uptake of Water and Solutes by Plant Roots¹

Abstract

Abstract A theory describing the hydraulic and osmotic transport of water and the diffuse, convective and active transport of solutes across root membranes is formulated. The theory predicts the dependence of the ratio of the osmotic pressures of the nutrient and xylem solutions and of the solute flux upon the rate of water uptake. The theory also predicts a nonlinear relationship between the flux of water and the pressure difference across root membranes. The results are shown to be in good qualitative agreement with a variety of observations on simultaneous uptake of water and solutes.