In vitro propagation, DNA content and essential oil composition of Teucrium scorodonia L. ssp scorodonia

Teucrium scorodonia ssp. scorodonia is a valuable medicinal plant. It is rare in Poland, therefore availability of raw material is limited and an effective method of producing in vitro-derived plants for pharmaceutical reasons would be desirable. However, the protocol for micropropagation of this species has not been developed yet. Here, its regeneration ability on media supplemented with different growth regulators was evaluated using shoot tip and nodal segment explants. Murashige and Skoog (MS; Physiol Plant 15:473-497, 1962. doi:10.1111/j.1399-3054.1962.tb08052.x) medium supplemented with indole-3-acetic acid (IAA) (0.1 mg L-1) and 6-benzyladenine (BA) (2 mg L-1) was the best for multiple shoot induction, resulting on average in about 7 and 8 axillary shoots per shoot tip and nodal explant, respectively, within 5 weeks. Flow cytometric analysis revealed that most of the in vitro-developed shoots of T. scorodonia possessed similar nuclear DNA content as seedlings (about 2.1 pg/2C). In vitro rooting of shoots was achieved at 100 % efficiency on MS medium without growth regulators or containing auxin. The addition of auxin, IAA, indole-3-butyric acid (IBA) or alpha-naphthaleneacetic acid (NAA) led to an increase in the number of roots. Rooted plantlets were transferred into ex vitro conditions and further grown in the field, where they matured and flowered. The essential oils from aerial parts of the in vitro-originated plants and their seed-derived counterpart were isolated and analyzed by gas chromatography-mass spectrometry (GC-MS). In the oils, 84 components were identified. Although the essential oils from the micropropagated plants and the seed-derived plants were qualitatively similar, quantitative differences were found.