Effect of Growth Regulators on In Vitro Callogenesis and Regeneration of Atropa Belladonna

Belladonna (Atropa belladonna), from Solanaceae, is an annual plant and has an important tropane alkaloids called hyoscyamine. Considering the pharmacological and economic importance of A. belladonna and priority in its domestication and cultivation, advances in its tissue culture and regeneration methods of this plant under in vitro conditions is important to facilitate methods of gene transfer to this medicinal herb. So, in this research, optimization of cultivation conditions for callogenesis and regeneration of Atropa belladonna was investigated. For callogenesis, belladonna sterilized seeds were initially sown in MS medium. After seed germination and seedlings growth for two months, stem and leaf explants were cultured in MS medium including a combination of different hormonal concentrations of 2.4-D (0, 0.5 and 1 mg/l) and Kin (0, 1 and 2 mg/l).To evaluate the regeneration percentage of callus from shoot explants, Kin hormone was used in four levels (0, 3, 5 and 8 mg/l) using completely randomized design with three replications. These experiments indicated that, shoot explants had the highest callogenesis in terms of explant type. In terms of hormonal concentrations, combination of two hormones at concentrations of 2.4-D 1 mg/l + Kin 2 mg/l+MS and also, 2.4-D 1mg/l +Kin 1mg/l +MS showed the highest rate of callogenesis. Increase in the concentration of Kin hormone in MS medium was directly correlated with increase in regeneration percentage and the highest regeneration rate of 36.66% was observed at 8 mg/l.