In Vitro Reproduction and Ex Situ Growth and Development of the Rare Species Lilium pensylvanicum Ker.-Gawl. (Liliaceae)

Abstract

The feasibility of applying higher plant biotechnology methods and approaches to conservation and propagation of Lilium pensylvanicum is demonstrated. Using seeds as the primary explants enables one to introduce this species into an in vitro culture while not causing harm to mother plants. Subculturing aseptic bulbs on a Humburg medium with halved composition of salts of macro- and microelements and enriched with kinetin (5 mg/L) and indoleacetic acid (1 mg/L) gives rise to the formation of 3 ± 1 bulbs per explant. Subsequent passages on four different variants of culture medium identifies the Murashige and Skoog medium supplemented with 6-benzylaminopurine (0.4 mg/L) as the most suitable for promoting the bulb development and offshoot growth. Rooting is carried out on hormone-free media. Years-long observations over the acclimatization of ex situ regenerated plants have been performed for the first time. The 5-year-long field observations over the survival, growth, and development of regenerated plants (n = 30) under the conditions of the collection nursery of Yakutsk Botanical Garden show that 77% of specimens have been acclimatized successfully. Mass flowering and fruiting is observed to take place in the fourth year. The identified ontogenetic developmental features of young plants are the morphological polyvariety of flowers and a high variability of the stem height. The developed protocol of clonal micropropagation of Lilium pensylvanicum, along with the results of many years of observations over the growth of regenerated plants, suggest that this method can be recommended for propagation of declining cenopopulations.