Sourcing and Propagation of Pontechium maculatum for Horticulture and Species Restoration

SIMPLE SUMMARY: Russian bugloss, a species of ornamental, apicultural and medicinal value, is threatened in some Central European countries. To restrict its overexploitation from nature the alternative method of propagation using tissue culture was elaborated here. Additionally, the generative reproductive ability was compared for two groups of plants obtained from seeds (received from Germany and representing the Polish vanishing population) and those of in vitro origin. It was proved that the German seed-origin plants had the greatest propagation efficacy and developed the greatest number of seeds. The ability of seeds to germinate was similar for all plants; however, seeds were in a state of dormancy, which can be broken using plant growth regulators. It was also proved that cultivation in vitro can induce some variability among received plants, which makes this way of Russian bugloss propagation a potential breeding tool. ABSTRACT: Pontechium maculatum, a species of ornamental, apicultural, health and medicinal value, is threatened in some Central European countries including Poland. Its propagation using seeds or in vitro techniques is needed for multiple applications including conservation. Generative propagation efficacy of P. maculatum plants representing different genetic resources (received from botanical gardens in Germany and in Poland) propagated from seeds or in tissue culture was assessed. Moreover, an efficient technique of propagation of P. maculatum using in vitro shoot culture from seedlings was elaborated for the first time. The highest propagation efficacy was noted for German plants of seed origin. The ability of seeds to germinate was similar for all plants; however, seeds were in a state of dormancy, which was broken by GA(3). After two years of storage, the seeds still retained the ability to germinate though seeds from propagated in vitro plants germinated more poorly than those from seed-originated plants. The ploidy assessment showed that some in vitro-origin plants had altered DNA content. The results indicate that efficacy of generative propagation of P. maculatum is resource dependent. Furthermore, results suggest that cultivation in vitro influenced some generative features of examined species, which makes this way of P. maculatum propagation a valuable source of genetic variation and a potential breeding tool.