Effects of different calcium concentrations on in vitro shoot and root development in Gök Üzüm (Vitis vinifera L.) cultivar

In this study, the effects of different calcium (CaCl₂·2H₂O) concentrations on shoot development, shoot tip necrosis (STN), and rooting were investigated in the Gök Üzüm (Vitis vinifera L.) cultivar under in vitro conditions. During the first subculture, although shoot formation was promoted in the 1 mg L⁻¹ BAP treatment, the STN rate was found to be high. Culture media containing 120, 180 and 240.0 mg L⁻¹ CaCl₂·2H₂O provided significant increases in parameters such as shoot length, number of nodes and leaf area compared to MS and BAP media. In addition, STN formation was completely eliminated at 180 and 240.0 mg L⁻¹ calcium levels. The hormone-free MS0 medium gave the lowest values in all parameters. The suppression of STN was associated with the stabilizing effect of Ca²⁺ ions on the cell wall and the maintenance of plasma membrane integrity. In addition, Ca²⁺ plays an important role as a signaling element in plant physiology and influences hormonal regulations, particularly those related to auxin transport. During the rooting the highest root fresh weight was obtained with 240 mg L⁻¹ CaCl₂·2H₂O, indicating the contribution of calcium to root tissue development and integrity. The findings revealed that calcium enhances plantlet quality both morphologically and physiologically. Consequently, culture media enriched with 180–240 mg L⁻¹ CaCl₂·2H₂O have the potential to increase the efficiency of grapevine micropropagation by promoting shoot development, reducing STN, and supporting root formation. Further studies are recommended to comprehensively evaluate the roles of different calcium sources and application strategies in plant tissue culture.