In vitro microrhizome induction in Acorus calamus L., - A commercially important aromatic medicinal plant

Acorus calamus L., is a leading aromatic medicinal plant that produces pungent aromatic rhizomes that are valued worldwide as an important herbal medicine and is one of the main ingredients in several polyherbal formulations used for neurological and metabolic disorders. The present investigation aims to develop an efficient protocol for in vitro microrhizome induction in A. calamus for the large-scale production of disease -free planting material for commercial purposes. In vitro derived shoots were initiated on MS medium supplemented with different concentrations of sucrose alone (3-10 %) and different concentrations of sucrose (6 % and 7 %) with varying concentrations of BAP alone (0.5-2 mg/L) and combinations with IAA (0.5 and 1 mg/L) and NAA (0.5 and 1 mg/L) were carried out for the microrhizome induction experiments. In different concentrations of sucrose used, healthy and disease -free microshoots of A. calamus were obtained in MS media supplemented with 7 % sucrose followed by 6 % sucrose. The highest shoot length (24.79 +/- 0.03 cm) and microrhizome size (4.98 +/- 0.03 cm length and 399.60 +/- 0.37 mg fresh weight) were obtained in MS solid medium supplemented with 1 mg/L BAP and 0.5 mg/L NAA with 7 % sucrose followed by the same hormone concentration with 6 % sucrose (shoot length -23.68 +/- 0.03 cm, microrhizome length- 4.68 +/- 0.03 cm and fresh weight of microrhizome-376.60 +/- 0.57 mg). The developed protocol can be used for large-scale production of disease -free propagules without rooting and acclimatization and enhance the production of true -to -type planting material.