THE EFFECTS OF AMMONIUM ON GROWTH, ACCUMULATION OF FREE AMINO-ACIDS AND NUTRITIONAL-STATUS OF YOUNG PHOSPHORUS DEFICIENT STRATIOTES ALOIDESPLANTS

Turions of Stratiotes aloides L. were grown at different ammonium leve ls under phosphorus deficient conditions in a staged gradient. After 1 3 weeks the plantlets appeared to be severely phosphorus deficient wit h the growth being seriously impaired. Nitrogen in the plants appeared to be predominantly present as soluble amino acids. This indicates th at net protein synthesis was seriously disturbed. Asparagine was by fa r the dominant soluble amino acid in the plantlets. At the highest ext ernal ammonium levels, net growth was significantly retarded when comp ared with the other concentrations with free ammonium accumulating in the plants. Ammonium uptake under phosphorus deficient conditions stro ngly increases nutrient imbalances in the plants, and thus their vital ity.