Gibberellic acid enhances growth, bulblet formation, and secondary metabolite accumulation in Eleutherine bulbosa (Mill.) Urb

Eleutherine bulbosa is a medicinally important plant, yet strategies to enhance both yield and bioactive compound content remain limited. This study investigated the role of gibberellic acid (GA₃) in bulblet induction from mother bulbs and subsequent growth responses in 6-week-old plants. Different GA₃ concentrations were tested independently at each stage, and the most effective treatments were then applied sequentially. GA₃ at 30 ppm applied to mother bulbs significantly promoted bulblet initiation, increasing fresh and dry mass, bulb length, and respiration activity. At the 6-week growth stage, GA₃ at 40 ppm stimulated biomass accumulation and secondary metabolite production, whereas 50 ppm exerted an inhibitory effect. Flavonoid and polyphenol levels increased under GA₃ application, with maximum accumulation observed at 40–50 ppm depending on the developmental phase. Sequential treatments combining 30 ppm at planting and 40 ppm during later growth achieved the greatest improvements in bulb productivity as well as flavonoid and polyphenol enrichment. The findings also highlight potential physiological links among respiration intensity, carbohydrate reserves, and secondary metabolite biosynthesis.