The Effects of GA₃ and AsA Applications on Vegetative Growth During Acclimatization

In vitro micropropagation enables the rapid and season-independent production of healthy plantlets, yet its long-term success largely depends on minimizing losses during the acclimatization phase. Because the culture vessels contain high humidity and free surface moisture, plantlets develop insufficient cuticles, which makes them highly vulnerable to desiccation when transferred to external conditions. Therefore, implementing supportive exogenous treatments during acclimatization is essential to enhance plantlet tolerance and reduce mortality. This study was conducted to evaluate the effects of gibberellic acid (GA₃) and ascorbic acid (AsA) applications on reducing losses encountered during the acclimatization process and improving the adaptation success of micropropagated plantlets under in vitro conditions. Survival rate (%), plant height (cm), shoot diameter (mm), number of leaves (pieces/plantlet), number of nodes (pieces/plantlet), and chlorophyll content (SPAD) were measured. The results revealed that the highest survival rate (51.33%) was obtained from 25 ppm GA₃ + 300 mg L⁻¹ AsA, the longest shoots (18.40 cm) from 25 ppm GA₃ + 300 mg L⁻¹ AsA, the thickest shoot diameter from 25 ppm GA₃ + 300 mg L⁻¹ AsA (1.88 mm), the highest number of leaves (15.00 pieces/plantlet) from 25 ppm GA₃ + 150 mg L⁻¹ AsA and 50 ppm GA₃ + 300 mg L⁻¹ AsA, the highest number of nodes (14 pieces/plantlet) from 50 ppm GA₃ + 300 mg L⁻¹ AsA, and the highest chlorophyll content (43.49 SPAD) from 25 ppm GA₃. The study demonstrates that combinations of GA₃ and AsA can be effective in reducing acclimatization losses.