The influence of potassium and calcium ions on nitrogen metabolism of cucumber seedlings

Abstract

It was found that K⁺ or Ca²⁺ deficiency in a nitrate or ammonium medium increased the amount of accumulated total and non-protein nitrogen in some organs of cucumber seedlings, as also caused changes in accumulated potassium and calcium. Lack of K⁺ or Ca²⁺ in a medium which did not contain nitrogen led to an increased level of glutamate dehydrogenase, alanine aminotransferase and aspartate aminotransferase activity in the cotyledons and roots of cucumbers. Similar changes in the activity of these enzymes were noted in certain organs of seedlings growing in nitrate or ammonium medium with decreased K⁺ or Ca²⁺ contents, although the magnitude of these changes depended upon the applied dosage of these cations, the form of mineral nitrogen, developmental phase of plants and the plant organ dealt with.