Yield, quality, and nutrient status of `Bridal Pink' (on R. manetti rootstock) roses were evaluated under increasing NaCl salinity and mixed NO3–/NH4+ nutrition. Container-grown plants were irrigated over eight flushes of growth and flowering with nutrient solutions having 100 NO3- : 0 NH4+, 75 NO3– : 25 NH4+, and 50 NO3– : 50 NH4+ ratios in combination with three NaCl concentrations. During the first four flowering flushes, NaCl was supplemented at 0, 5, and 10 mm, but these concentrations were increased to 0, 15, and 30 mm during the last four flushes. Interestingly, NO3– : NH4+ ratios and NaCl concentration had no main effects over any flower yield or quality component evaluated over the 13-month experimental period. Furthermore, visual symptoms of apparent salt injury were just observed during the last three flowering cycles, and mostly on the oldest foliage of plants receiving the highest salt concentrations (30 mm). Leaf N and Na concentrations were not significantly affected by the treatments over the course of the experiment, averaging 3.34% and 45 mg·kg–1, respectively. Leaf Cl concentrations were significantly increased by salt additions, ranging from 1000 to 15,000 mg·kg–1 [0.1% to 1.5% dry weight (DW)]. Correlation analyses revealed that relative dry weight yields increased with leaf Cl concentrations up to 3000 mg·kg–1 (0.3% DW) but were significantly depressed at higher concentrations. These results confirm recent reports suggesting that roses are more tolerant to salinity than their typical classification of sensitive. Furthermore, this is the first known study to report an apparent positive effect of moderate leaf Cl concentrations on rose biomass yields.
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