Direct Organogenesis and Plantlet Establishment via Cotyledon Explants in Medicinally IDirect Organogenesis and Plantlet Establishment via Cotyledon Explants in Medicinally Important Herb Silybum marianum (L.)mportant Herb Silybum marianum (L.)

Abstract

Objectives: The species Silybum marianum (L.) (Asteraceae) commonly known as Milk thistle is medicinally valuable and due to over exploitation the species may become threatened. Hence, we have made an attempt to optimize the protocol for its direct regeneration through cotyledon explants using in vitro culture technology. Methods/Statistical Analysis: For in vitro multiple-shoot induction, cotyledon explants were excised from surfacesterilized seeds and cultured on MS Basal Medium (MBM) enriched with diverse conc. (10.0–20.0 μM) of BAP/KIN alone and also 10.0 μM BAP/KIN in combination with 1.25–5.0 μM NAA/IAA/IBA. The micro-shoots were cut out and cultured on 1/2 strength MBM enriched with diverse concentrations (5.0-20.0 μM) of NAA/IAA/IBA alone and also coupled with 1.25–5.0 μM BAP/KIN. Findings: In this study, superlative rate of shoot induction, maximal Number of Shoots Per Explant (NSPE) and longest shoot-length were achieved on MBM enriched with 10.0 μM BAP + 2.5 μM NAA. Superlative rate of root induction, mean number of roots per shoot and mean root length were documented on MBM supplemented with 15.0 μM NAA + 2.5 μM BAP. Application/Improvement: Being over exploited, the current technique can be operated for accelerated multiplication and conservation of the species. Further, this protocol can also be operated for transfer of novel genes for enhancement and modulation of bioactive molecules production in S. marianum – a medicinally valuable plant.