Advances in Biology & Earth Sciences

This study investigates the effects of varying concentrations of nitrogen components -specifically potassium nitrate (KNO₃) and ammonium nitrate (NH₄NO₃) - on the in vitro growth dynamics of the Shirvan Shahı grapevine cultivar (Vitis vinifera L.). Using Murashige and Skoog (MS) medium as the base, different modifications of nitrogen content were tested individually and in combination. The results showed that a 3/4 concentration of combined NH₄NO₃ and KNO₃ significantly enhanced shoot length (5.20 cm), leaf number (7.2) and biomass (560 mg), outperforming the full MS control. In contrast, the lowest concentrations led to decreased vegetative parameters. The findings confirm that not only the presence but also the balance and form of nitrogen are critical for optimal morphogenesis in grapevine micropropagation. The synergy between ammonium and nitrate at moderate levels proved to be the most effective approach for stable in vitro development. These results contribute to optimizing nitrogen formulation in culture media, offering practical guidance for improving clonal propagation protocols of sensitive grapevine cultivars.