Nitrogen and Cation Nutrition of Three Ecologically Different Plant Species

Abstract

AbstractExperiments on nutrient requirements of the ecologically very different plant species Betula verrucosa Ehrh., Cucumis sativus L., and Vaccinium vitis idaea L. are discussed with regard to the nitrogen and cation nutrition. The nutrient solution technique used allows a strict control of nitrogen source and cation uptake at maximum growth rate.The nitrogen sources were equally efficient except for growth reductions in cucumber at ammonium nutrition. Increase in tissue pH resulting from a high total uptake rate of NH4+ and other cations is probably an important factor in ammonium toxicity. No evidence was found for the concept of “ammonium plants”; but at high nitrate supply to Vaccinium a high cation uptake may account for decrease in growth rate.No large or fundamental differences in cation or anion requirements among the species were found; the difference in ion balance (C — A) in relation to dry matter depends mainly on differences in xeromorphy.In cucumber, the relations between cation and nitrate nutrition are in agreement with models proposed in the literature. Vaccinium and birch have a cation uptake and retention of high efficiency at low nutrient availability and ammonium nutrition indicating independence between cation and nitrate nutrition in these species.The properties found are regarded as significant and functional in relation to the ecological character of the species.