Changes in plant growth substances, contents and flower quality of rose cv. Dolce Vita' in response to nitrogen sources under soilless culture conditions

The aim of this study was to investigate the biochemical responses and vase life of rose cut flowers under different ratios of NO3:NH4:urea in soilless culture. In this study, urea was used as the source of nitrogen (N) in solution cultures. For this purpose, an experiment was conducted as completely randomized design with seven ratios of N forms and three replications. The rooted cuttings of rose cv Dolce Vita were supplied with seven different ratios of NO3-:NH4+:urea (100:0:0, 70:15:15, 50:25:25, 50:0:50, 0:0:100, 50:50:0 and 0:100:0). Results showed that with the increase in urea and ammonium concentrations, the amounts of cuttings IAA, GA(3), zeatin, ABA and polyamines contents decreased significantly. Plants fertigated with nutrient solution containing NO3-:NH4+:urea (50:25:25) had the highest concentrations of growth regulators, the highest stalk length and flower vase life. As the ammonium ratios in the nutrient solution increased, the flower vase life decreased significantly. It was concluded that using NO3-:NH4+:urea at the ratio of 50:25:25 had the highest effects on improving the rose cut flowers quality by affecting plants growth regulators and can be recommended for cut rose production in soilless culture systems.