INDUCTION OF CALLUSOGENESIS AND ORGANOGENESIS OF MOLDAVIAN DRAGONHEAD (DRACOCEPHALUM MOLDAVICA L.) IN VITRO
Dracocephalum moldavica L. (Moldavian dragonhead) is a medicinal plant with a number of useful actions (anti-inflammatory, soothing, firming, analgesic, antiseptic properties, etc.), because of which it is used in folk and officinal medicine. Having a lemon flavour, it is used in perfumery, as a perfume in soap and detergents, in food service industry, decorative art, beekeeping (as a good honey plant). Such a wide range of applications is facilitated by the secondary metabolites contained in it. However, the percentage and component composition of the essential oil vary greatly depending on the dragonhead variety and growth conditions. This can be avoided for the case of in vitro culture, which allows controlling, changing and maintaining the cultivation conditions. In addition, for industrial synthesis of substances used for making medicinal products, a suspension culture is used in bioreactors, which can be obtained from callus when transferring it from an agar nutrient medium into a liquid medium. Therefore, there is a necessity to determine the optimal conditions for callus induction. In the research, the authors studied the characteristics of the callusogenesis and organogenesis of Dracocephalum moldavica in vitro. Stem (internodes) and leaf (blades and petioles) explants, obtained from 1-1,5 months' old Moldavian dragonhead plants, were placed on nutrient media with a different hormonal composition. The Murashige and Skoog nutrient medium (MS) was taken as a basis. After a month of cultivation, the frequency of callusogenesis, organogenesis, colour and external appearance of callus, and the condition of explants were recorded. The study has revealed differences in the analyzed processes between two dragonhead varieties and three explant types. Internodes and leaf petioles have proved to have the best regenerative ability. Callus formation of Dracocephalum moldavica runs most effective on these explant types on nutrient media with the addition of 0,2...2,0 mg/l of 2,4-D, and also at a combination of 0,2 mg/l of 2,4-D or 0,5 mg/l of IBA with 1,0 mg/l of BAP or kinetin. The studied hormonal compositions of the MS nutrient medium do not lead to the induction of stem organogenesis. Induction of rhizogenesis of Dracocephalum moldavica from leaf and stem explants is best performed on MS nutrient medium with an addition of 0,5 mg/l of IBA.