In Vitro Growth, Morphogenesis, and Acclimatization of Endangered Rindera umbellata (Waldst. & Kit.) Bunge

Abstract

Rindera umbellata (Waldst. & Kit.) Bunge is a rare, critically endangered and horticulturally appealing plant with unexplored pharmaceutical potential. Its distribution is restricted to sandy habitats, whereas propagation in nature is limited by fungal infections of the seeds. To initiate its ex situ conservation and provide material for metabolomic studies, we have introduced R. umbellata into in vitro culture using immature embryos as primary explants. A 72% of the embryos germinated on growth regulator-free medium. The optimization of growth conditions was based on varying carbohydrates (sucrose, glucose, and fructose) in the medium. In vitro growth and development of R. umbellata plants were significantly affected by both the type and concentration of the applied sugars. For most recorded parameters, including leaf elongation, biomass production, rooting percentage, and the number and length of roots, 0.1 m sucrose was optimal. The highest percentage of explants with developed buds was achieved on 0.06 m sucrose (38.77%) or 0.3 m glucose (27.43%). The plantlets obtained on 0.1 m sucrose were successfully acclimatized to greenhouse and field conditions with survival rates of 71.43% and 42.86%, respectively. To our best knowledge, this is the first publication dedicated to this species.