Optimization of tissue culture and regeneration in Valerian (Valeriana officinalis) medicinal plant

Valerian is one of the most important herbs in Iran. Regarding the importance of this plant in traditional and industrial medicine, in this research, optimization of tissue culture, callus induction, and regeneration of whole plant from two types of leaf and petiole explants were evaluated on various hormone combinations. The results showed that the leaf segment is more suitable for callugenesis in both light and dark conditions. The highest amount of callus was obtained in light conditions for the leaf explant cultured on the medium containing 0.5 mg/L BAP and 1 mg/L BAP. Dark-induced calli did not show the potential to shoot regeneration on tested media containing different concentrations of BAP and TDZ, and only callus growth and root formation was observed. The light-induced calli from the leaf explants had a good potential to regenerate shoots on the regeneration medium. Maximum mean number of shoots was observed in the regeneration medium containing 3 mg/L BAP. These results provided basic information on the effects of some physical and chemical factors on the tissue culture and regeneration of Valerian. Also, we introduce an efficient system for shoot regeneration in this plant that can be used in molecular breeding programs using genetic engineering techniques.