"The significance of ion exchange in biological alkali metal uptake"

Abstract

The literature of the uptake of cations by biological systems is reviewed. It is found that the present data can only be explained by postulating chemical phenomena which have not yet been discovered. The work done investigates these phenomena and the following results have been obtained: Part I (a) Investigation of calcium-saturated carboxyl resin (Zeocarb 226) has shown that there is some residual cation-exchange capacity for monovalent cations. (b) This residual capacity has a selectivity coefficient in favour of K+ over Na+ ions. (αK+ Na+ = 2.5). (c) These reactions are slower than would be expected for a normal ion-exchange reaction. (d) Although these phenomena have been discovered they are quite inadequate to explain the uptake of monovalent cations by plant roots. Part II (a) Phosphate-saturated anion-exchange resin (De-Acidite FF) forms complexes with cations, the ones investigated being Na+, K+, Rb+, and Cs+. (b) The selectivity pattern of the uptake was Cs+, Rb+ > K+ > Na+. (c) The selectivity coefficient, αK+ Na+, for this system was about 2.5. (d) These phenomena were insufficient to explain all the facets of sodium-potassium balance of living cells. These results are considered from the aspect of a number of theories on ion-exchange.