Callus mediated shoot organogenesis and regeneration of cytologically stable plants of Ledebouria revoluta: An ethnomedicinal plant with promising antimicrobial potency.

Ledebouria revoluta are important ethnomedicinal plant found in India and South Africa. Micropropagation via indirect shoot organogenesis had been established from three types of explant (i.e. scale leaf, leaf lamina and root) of L. revoluta. Scale leaf was found superior as compared to leaf lamina and root explant with respect to their organogenic callus induction potentiality. Murashige and Skoog (1962) [MS] media supplemented with 3.0 mg L(-1) 2,4-dichlorophenoxyacetic acid, 0.75 mg L(-1) β-naphthoxyacetic acid were best effective for inducing organogenic callus. Maximum 17.0 ± 0.52 bulblets were induced from about 500 mg of callus within 42-46 days sub-culturing on a medium containing 0.75 mg L(-1) kinetin. The bulblets were matured (86.7% success) after one month culture on the same medium composition. The best result of in vitro root induction with 100% response and 8.4 ± 0.31 roots per bulb was achieved after 18 days of implantation on MS medium containing 2.0 mg L(-1) indole-3-butyric acid. Plantlets were acclimatized with a 96.0% survival rate. Chromosomal studies revealed cytological stability of callus cells and all regenerants containing 2n = 30 chromosomes, same as parental plants. Antimicrobial activity of L. revoluta was tested against two Gram-positive bacteria, three Gram-negative bacteria and two fungi. The methanol and ethanol extract proved more effective against bacteria, whereas acetone and chloroform extract shows potential anti-fungal activities. Present protocol can be applied reliably to produce uniform planting materials in large scale. In addition, this efficient indirect regeneration pathway via callus culture opens a way for improvement through genetic transformation.