ABSTRACT
152The foliar uptake of inorganic solutions of potassium, manganese, and cobalt was studied in laboratory tests using detached leaves of two potato cultivars. In addition, the uptake of inorganic solutions of cobalt and calcium was tested in the field using the crop canopy of one cultivar. In both situations, cation uptake was shown to be greatly influenced by the accompanying anion or by the inclusion of a chelating agent (EDTA). Chloride, thiocyanate, and nitrate salt solutions exhibited greater cation uptake than the sulfate salt or ethylene diaminetetraacetic acid (EDTA) solutions. These differences were attributed to restrictions on anion uptake based on cuticle permeability and solubility effects. In the field, the additional factor of morphological and microenvironmental differences in the canopy did not have a significant effect. This was possibly due to the modifying effect of Tween-20 and on incomplete droplet drying at the high humidity levels within the sheltered canopy.
