ISHS Acta Horticulturae 424: II International Rose Symposium
THE UPTAKE OF NITRATE AND AMMONIUM BY GREENHOUSE ROSES. |
| Authors: | R.I. Cabrera, R.Y. Evans, J.L. Paul |
| Abstract:
A recirculating hydroponic system was used to study the uptake of nitrate and ammonium by 'Royalty' rose plants under controlled pH and nitrification conditions. Regardless of the nitrogen source used, uptake rates followed a cyclical pattern that was related to flower shoot development and harvest. The lowest uptake rates occurred when the shoot elongation rate was at its maximum, and the highest uptake rates occurred at about the time the flower shoot reached commercial maturity. Nitrogen uptake rates for plants supplied with NH4+ or NO3- + NH4+ were similar or higher than those of plants provided with NO3- alone. Nitrogen form had no significant effect on flower yield, flower quality, or leaf tissue N composition. Under conditions of controlled rhizosphere acidity the regulation of nitrogen uptake at the whole plant level appears to be similar for both NH4+ + and NO3-. | |
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