Effects of sterilization methods and plant growth regulators on in vitro regeneration and tuberization in Gloriosa superba (L.)

This study evaluated the effect of plant growth regulators and sterilizing agents on in vitro propagation and micro-tuberization of endangered Gloriosa superba L. It also assessed culture contamination and plantlet survival. Cultures without sterilization showed contamination, emphasizing the necessity of sterilization. Contamination decreased with higher sterilizing agent concentrations and exposure times. When using 7.5% H<inf>2</inf>O<inf>2</inf> for 5 min, contamination was reduced to 7.14%, and survival increased to 89.29%. Treatment with 10% H<inf>2</inf>O<inf>2</inf> for 5 min exhibited 82.14% viability and no contamination. Similar trends were seen for HgCl<inf>2</inf> and NaOCl, though NaOCl was less effective. Using full-strength Murashige and Skoog (MS) medium with 2.0 mg L⁻¹ BAP and 0.5 mg L⁻¹ NAA, surface-sterilized tuber explants displayed 90.63% bud break, 6-d average for bud break, ≥ 3 shoots per explant, and significant elongation (5.13 cm). This novel approach established Gloriosa superba L. whole plants from non-dormant corm bud explants, bypassing rooting. The plantlets grown in a controlled environment have successfully acclimatized and can survive at a rate of 80% after being transplanted. MS medium with 1.0 mg L⁻¹ BAP, 4.0% sucrose, and 16-h photoperiod produced 5.75 in vitro root tuber sprouts per non-dormant corm bud explant and an 82.14% tuberization rate, yielding clean, non-callusing microtubers with unique white appearance—a remarkable achievement in a brief duration, revolutionizing protocol efficiency.