Overcoming dual seed dormancy and enhancing in vitro seedling development of Gloriosa superba (L.) with a targeted sterilization approach and plant growth regulator synergy.

The status of Gloriosa superba L. in the wild has been declining due to over-collection and habitat destruction. Intrinsic severe seed dormancy and low germination rates hinder the cultivation process. To conserve this plant, in vitro culture protocols have been developed to enhance seed germination and seedling growth. An effective sterilization method involving 0.15% mercuric chloride (HgCl₂) for 8 min was found to eliminate contamination and yield a 100% survival rate, resulting in disinfested seeds and robust seedling growth. The most successful treatment consisted of Murashige and Skoog (MS) medium with 1.5 mg⋅L^-1 GA₃ and 1.5 mg⋅L^-1 BAP, along with 4% sucrose under a 16-h photoperiod, which achieved the highest average in vitro seed germination (9.25 out of 12 seed explants) and an impressive overall seedling survival rate of 77.08% after 30 d. Subsequent growth of two-week-old seedlings on MS medium with 1.5 mg⋅L^-1 BAP and 1.0 mg⋅L^-1 NAA supplemented with 30 g⋅L^-1 sucrose and a 16-h photoperiod resulted in the greatest average seedling length (5.83 cm) and seedling root length (4.08 cm) after four weeks. Transferring the excised shoots of in vitro-grown seedlings to half-strength MS medium with 1.0 mg⋅L^-1 IBA led to maximum root induction (84.37%) and further enhanced root development. These in vitro-grown plantlets were successfully acclimatized and transplanted under field conditions, with a 60% survival rate after 11 weeks. [ABSTRACT FROM AUTHOR]