Direct shoot regeneration from intact leaves of Arnebia euchroma (Royle) Johnston using thidiazuron

The present study highlights the importance of preculture time and concentration of TDZ (thidiazuron) for direct regeneration from in vitro leaves (attached to shoots) in Arnebia euchroma. Shoot buds proliferated to form multiple shoots on MS medium (Murashige and Skoog medium) with 5.0 mu M Kn. Different additives viz, ascorbic acid, PVP (polyvinylpyrrolidone), PVPP (polyvinylpolypyrrolidone) or activated charcoal (50, 100 and 250 mg/l each) were used to check the phenolic exudations. Direct shoot regeneration was obtained when shoots were initially precultured for 40 days on medium with a higher concentration of TDZ (20.0 mu M) and then transferred to a lower concentration (5.0 mu M TDZ). The identity of shoot buds was confirmed by histological studies. Regenerated shoots were cultured for 30 days on medium containing Kn (5.0 mu M) for proliferation and then transferred to IBA (0.25 mu M)-containing medium for rooting. Rooted plantlets were transferred to greenhouse with 45-50% survival.