Regeneration of in vitro plants through direct and indirect organogenesis from Dracocephalum rupestre leaf explants

Abstract

Leaf explants of Dracocephalum rupestre were utilized for regeneration employing direct and indirect differentiation pathways. Results revealed that the direct regeneration medium for leaf explants consisted of MS + 2 mg/l 6-BA + 0.1 mg/l KT + 0.05 mg/l NAA, yielding a differentiation rate of 63.46%. The induction medium for callus was composed of MS + 2 mg/l 6-BA + 0.1 mg/l 2,4-D + 0.5 mg/l IAA, resulting in an induction rate of 86.73%. For the differentiation of adventitious buds, the medium included MS + 2 mg/l 6-BA + 2 mg/l TDZ + 0.05 mg/l IAA, with a differentiation rate of 53.48%. The proliferation medium for adventitious buds generated through both pathways, comprised MS + 2 mg/l 6-BA + 0.05 mg/l NAA, with proliferation rates of 83.57% and 87.41%, respectively. The rooting medium suitable for both methods was 1/2MS + 0.1 mg/l NAA + 0.1 mg/l IBA, resulting in rooting rates of 83.69% and 79.15%, respectively. Comparatively, the direct differentiation pathway proved to be more efficient and time-saving, with leaf explants requiring 30 days less for regeneration compared with the indirect pathway. This study provides theoretical and technical support for subsequent genetic transformation research of Dracocephalum rupestre.