Direct and indirect plant regeneration in Hypericum perforatum: an important medicinal plant

Hypericum perforatum L. (St. Johns’ wort) is the most commercially important species of the genus Hypericum and contains a wide range of components including naphthodianthrones, phloroglucinols, tannins, xanthones, phenolic acids and essential oil. A method for rapid micropropagation of Hypericum through plant regeneration from leaf and stem explant derived calli has been developed. The stem and leaf segments were cultured on MS medium supplemented with the combination of auxins and cytokinin for callus induction. Also, the best callaus induction treatment was selected for evaluation the effect of light and dark conditionon callus quality. By using sterile seedlings, effects of type and concentration of cytokinin and auxin were evaluated on the shoot, callus and root induction. The results showed that the medium containing low BA concentration (0.1mg/l BA) with 0.05 mg/l IBA is the best medium for producing maximum shoot number as well as normal shoots. However, high concentrations of BA (0.1 to 0.25 mg/l) were produced abnormal shoots. This plant also had high ability of shoot induction. These shoots were rooted easily even in culture medium free growth regulators.0.5 mg/l IBA was the best IBA concentration for root induction from produced shoots. Callus obtained from leaf explants had more growth in darkness. The highest callus fresh weight was observed on 0.25mg/l 2,4-D and 1 mg/l kin and also 0.5 mg/l 2,4-D and 1 mg/l BA. The plantlets were acclimatized and transferred to the greenhouse with 80% survival. This in vitro propagation protocol should be useful for conservation as well as mass propagation of this medicinal plant.

Keywords:

Hypericum perforatum L , Shoot formation , Callus induction , micropropagation