Abstract

Dog rose (Rosa canina) is one of the most important ornamental and medicinal plants which are used as rootstock for ornamental roses as Rosa hybrida and Rosa floribunda. The effects of different concentrations of NH₄NO₃ (10-15 and 20 mM), KNO₃ (15-20 and 25 mM) and NH₄:NO₃ratios (10:25, 10:30, 10:35, 15:30, 15:35, 15:40, 20:35 and 20:45) was investigated on proliferation stage of dog rose cultivated on Ms media with total nitrogen levels (35; 40, 45, 50, 55, 60 and 65 mM). The relative amounts of NH₄⁺ and NO₃^- ions influenced the tested parameters. The highest shoot length and most node numbers were obtained with 20:45 NH₄⁺:NO₃^- ratios. Chlorosis leaf number was less with 15:35 and 20:45 NH₄⁺:NO₃^- ratios. When NO₃^- was higher than NH₄⁺, shoot length and node numbers were produced more and chlorosis leaf number was decreased. This study also demonstrates that with increasing nitrogen levels, the growth of shoots and node numbers were more but leaf chlorosis was decreased, therefore proliferation was better. The percentage of axillary shoot was affected by NH₄NO₃ concentrations and it was highest in 20 mM concentration, but with increasing KNO₃, the leaf necrotic and feeble callusing percentage at the cut ends of explants were more and lower in row.

Key words: Dog rose, in vitro culture, MS nitrogen source, NH₄⁺: NO₃^- ratio, proliferation.