Abstract Since M. sinensis Anderss., M. sacchariflorus (Maxim.) Hack. and M. ×giganteus J.M.Greef & Deuter ex Hodk. and Renvoize have considerably the highest potential for biomass production among Miscanthus Anderss. species, there is an urgent need to broaden the knowledge about cytological characteristics required for their improvement. In this study our objectives were to assess the genome size variation among eighteen Miscanthus accessions, as well as estimation of the monoploid genome size (2C and Cx) of the M. sinensis cultivars, which have not been analyzed yet. The characterization of three Miscanthus species was performed with the use of flow cytometry and analysis of the stomatal length. The triploid (2n = 3x = 57) M. sinensis ‘Goliath’ and M. ×giganteus clones possessed the highest 2C DNA content (8.34 pg and 7.43 pg, respectively). The intermediate 2C-values were found in the nuclei of the diploid (2n = 2x = 38) M. sinensis accessions (5.52–5.72 pg), whereas they were the lowest in the diploid (2n = 2x = 38) M. sacchariflorus ecotypes (4.58–4.59 pg). The presented study revealed interspecific variation of nuclear DNA content (P<0.01) and therefore allowed for recognition of particular taxa, inter- and intraspecific hybrids and prediction of potential parental components. Moreover, intraspecific genome size variation (P<0.01) was observed in M. sinensis cultivars at 3.62%. The values of the stomatal size obtained for the triploid M. ×giganteus ‘Great Britain’ (mean 30.70 μm) or ‘Canada’ (mean 29.67 μm) and diploid M. sinensis ‘Graziella’ (mean 29.96 μm) did not differ significantly, therefore this parameter is not recommended for ploidy estimation.

Abstract An efficient micropropagation protocol for production of genetically uniform clones of Eryngium campestre L. was developed. To determine the effect of nutritional and hormonal factors on shoot and root development and bioactive compounds production, three variants of media differing in the content of macro- and micronutrients, as well as plant growth regulators of various types and concentrations were tested. The highest regeneration (100%), with over 13 shoots per explant, was induced on Murashige and Skoog (MS) medium with 1.0 mg l−1 benzyladenine (BA) and 0.1 mg l−1 indole-3-acetic acid (IAA). The in vitro derived shoots multiplied through axillary bud formation were rooted and transferred to an experimental plot with 78% frequency of survival. Flow cytometry showed no variation in nuclear DNA between the seedlings and micropropagated plants. Preliminary thin layer chromatography (TLC) analysis indicated that phenolic acids, saponins, flavonoids and acetylenes were present in plant biomass. Ultra high performance liquid chromatography (UHPLC) analysis revealed that shoots and roots from in vitro derived plants and root cultures maintained the ability to produce rosmarinic acid (RA), rosmarinic acid hexoside (RA-HEX) and chlorogenic acid (CGA). The highest phenolic acid content was detected in roots of in vitro regenerated plants. The extract from those roots expressed the highest inhibitory effect against bacteria Staphylococcus aureus, as well as dermatophytes Trichophyton mentagrophytes and T. rubrum.