Micropropagation, encapsulation and growth of Artemisia vulgaris node explants for germplasm preservation

As an alternative to seed propagation, an efficient micropropagation system and subsequent rooting were developed for the medicinal plant Artemisia vulgaris (Asteraceae). A maximum of 32.8 shoots were produced from the nodal explants cultured on 4.9 μM 2iP. The effect of different types and concentrations of carbohydrates was tested for multiple shoot induction and we found that sucrose at 3% concentration resulted into a better response. Healthy plantlets were transferred to garden soil:farmyard soil:sand (2:1:1) mixture (growing medium) for acclimatization, which was successful and subsequent maturity was achieved under garden conditions. Nodal segments were excised from proliferating shoot cultures and encapsulated in high density sodium alginate hardened by 50 mM CaCl2. 2.0% sodium alginate was determined to produce the highest quality encapsulated nodal segments beads because of the viscosity produced by 2.0% sodium alginate solution. When encapsulated nodal segments were stored at 5 °C they did not grow in light or dark conditions. All encapsulated nodal segments survived 20 weeks of 5 °C storage. In fact, 85% of encapsulated mugwort nodal segments survived refrigerated storage for 11/4 years (60 weeks) and after 3 months on proliferation medium, the nodal segments produced a similar result as compared to encapsulated segments either not stored at 5 °C or stored for 20 weeks at 5 °C. Thus a simple micropropagation and a cost-effective cold storage protocol for alginate encapsulated vegetative (node) explants of mugwort was successfully developed for the germplasm preservation of this valuable medicinal plant.