The effect of divalent cations on K and CI accumulation by slices of beetroot tissue has been studied. It is shown that CI uptake from solutions of (K+Ca) CI can be greater than from KCI solutions of the same CI concentration. It is considered that CI uptake limits K uptake by beet cells, and that Ca acts to increase the CI uptake. As a mechanism for this stimulation of CI uptake, it is suggested that uptake of the anion is limited by diffusion through a negatively charged surface or membrane, which will be more permeable to anions when divalent cations, rather than univalent cations, are the counterions.