Royal jelly as a novel bio-stimulant for asymbiotic seed germination andprotocorm development in Phalaenopsis

Orchid micropropagation is often limited by slow seed germination and early seedling development. This study evaluated the potential of royal jelly (RJ), a nutrient-rich organic substance, as a growth-promoting additive in the asymbiotic culture of five Phalaenopsis varieties viz., Nottingham, Dubrovnik, Andorra, Memphis, and Bucharest. A factorial experiment was conducted using two peptone concentrations (1/ gL{ 1 and 2/ gL{ 1) combined with four RJ levels (0, 150, 300, and 450/ ppm) in half-strength Murashige and Skoog (MS) medium. Results demonstrated that RJ significantly enhanced germination and seedling development in a concentration- dependent manner. The variety Nottingham cultured in 2/ gL{ 1 peptone medium supplemented with 300/ ppm RJ achieved the highest germination rate of 96.33%, reduced the time to protocorm formation by 2–3/ days, and increased leaf and root primordia numbers by 15–20% compared with the control. Higher RJ concentrations (450/ ppm) occasionally reduced germination and delayed early growth, indicating an optimal range for supplementation. These findings suggest that RJ can serve as an effective organic bio-stimulant for Phalaenopsis micropropagation, offering a sustainable alternative to conventional synthetic growth regulators. Future studies should isolate active compounds in RJ and assess its scalability across different orchid species.