The influence of nitrogen concentration and ammonium/nitrate ratio on N-uptake, mineral composition and yield of citrus
In short-term water culture experiments with different 15N labeled ammonium or nitrate concen trations, citrus seedlings absorbed NH; at a higher rate than No;. Maximum NO; uptake by the whole plant occurred at 120 mg L – 1 NO;-N, whereas NH; absorption was saturated at 240 mg L – 1 NH;-N. 15NH; accumulated in roots and to a lesser degree in both leaves and stems. However, 15NO; was mostly partitioned between leaves and roots.