The influence of accompanying cations on the foliar uptake of Na, K, Rb and Cs

Abstract The influence Na, K, Rb or Cs may have when accompanying one of these elements applied foliarly to bean plants has bean studied under controlled environmental conditions. No competition was found in the speed of initial penetration from the outer leaf surface to the protoplasts of epidermal cells between any two of the cations considered separately. The magnitude of penetration of Na, Rb or Cs. Retention in the treated area showed competition among the elements, Na being held more strongly when accompanied by Cs, Rb or K in that order. Presence of another cation influenced retention differently. Transport of Na was faster than of either K, Rb or Cs when applied together. K and Rb were transported simultaneously at equal rates, and either more than Cs. Total quantities transported were influenced differently by the various cations present and in turn determined the total quantities taken up by the plants.