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Abstract

We used chromosome data to verify the taxonomic affiliation of specimens previously recognized as Brachyactis ciliata. All analyzed plants were diploids based on x = 7 (2n = 2x = 14), the basic number characteristic for Symphyotrichum ciliatum, allowing the examined species to be shifted from the genus Brachyactis to the genus Symphyotrichum sect. Conyzopsis. The chromosome number (2n = 2x = 14) for specimens of S. ciliatum from Poland is reported for the first time.
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Abstract

Until recently, Festuca arietina was practically an unknown species in the flora of Eastern Europe. Such a situation can be treated as a consequence of insufficient studying of Festuca valesiaca group species in Eastern Europe and misinterpretation of the volume of some taxa. As a result of a complex study of F arietina populations from the territory of Ukraine (including the material from locus classicus), Belarus and Lithuania, original anatomy, morphology and molecular data were obtained. These data confirmed the taxonomical status of F arietina as a separate species. Eleven morphological and 12 anatomical characters, ITS1-5.8S-ITS2 cluster of nuclear ribosomal genes, as well as the models of secondary structure of ITS1 and ITS2 transcripts were studied in this approach. It was found for the first time that F arietina is hexaploid (6x = 42), which is distinguished from all the other narrow-leaved fescues by specific leaf anatomy as well as in ITS1-5.8S-ITS2 sequences. Molecular data indicating possible hybridogenous origin of F arietina, fall in line with the anatomical-morphological data and explain the tendency toward sclerenchyma strands fusion with formation of a continuous ring in F arietina, as well as E arietina ecological confinement to psammophyte biotopes.
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Abstract

Intraspecific changes in genome size and chromosome number lead to divergence and species evolution. Heavy metals disturb the cell cycle and cause mutations. Areas contaminated by heavy metals (metalliferous sites) are places where microevolutionary processes accelerate: very often only a few generations are enough for a new genotype to arise. This study, which continues our long-term research on Viola tricolor (Violaceae), a species occurring on both metalliferous (Zn, Pb, Cd, Cu) and non-metalliferous soils in Western and Central Europe, is aimed at determining the influence of environments polluted with heavy metals on genome size and karyological variability. The genome size of V. tricolor ranged from 3.801 to 4.203 pg, but the differences between metallicolous and non-metallicolous populations were not statistically significant. Altered chromosome numbers were significantly more frequent in material from the polluted sites than from the non-polluted sites (43% versus 28%). Besides the standard chromosome number (2n = 26), aneuploid cells with lower (2n = 18-25) or higher (2n = 27, 28) chromosome numbers were found in plants from both types of site, but polyploid (2n = 42) cells were observed only in plants from the metalliferous locality. The lack of correlation between chromosome variability in root meristematic cells and genome size estimated from peduncle cells can be attributed to elimination of somatic mutations in generative meristem, producing chromosome-stable non-meristematic tissues in the peduncle.
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Abstract

The authors report the first discovery of diploid populations of Hieracium naegelianum Panč. subsp. naegelianum and H. naegelianum subsp. ljubotenicum Behr & Zahn., and give the first chromosome counts for H. cernuum Friv., H. gymnocephalum Griseb. ex Pant., H. sparsum Friv., Pilosella pavichii (Heuff.) Holub and P. serbica (F. W. Schultz & Schultz-Bip.) Szeląg from Macedonia and/or Montenegro. A diploid chromosome count for Hieracium renatae Szeląg is confirmed based on material from the whole distribution range of the species. An emasculation experiment showed that all the analyzed diploid Hieracium taxa reproduce sexually.
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Abstract

We used germination tests to assess the frequency of polyembryony in 9 asparagus cultivars with a high propensity to produce double embryos with different ploidy levels: Alpha, Andreas, Boonlim, Cipres, Eposs, Helios, Limbras, Ravel and Sartaguda. Twin embryos inside a single seed were found in 3 cultivars: Eposs 2n, Ravel 2n and Sartaguda 2n, at 0.60% frequency (15 seeds with twin embryos out of 2500 seeds). Of 30 obtained seedlings, 14 were separated diploid-diploid twins, 6 were conjoined diploid pairs, 8 were separated diploid-haploid and 2 were diploid-haploid pairs conjoined in the hypocotyl region. Some embryos showed unilateral dominance of one embryo (size and shape). The haploid status of the smallest embryo was confirmed by chromosome number (n=x=10) and flow cytometry (nuclear C DNA amount 1.95 pg). The haploid obtained in this manner possessed enough vegetative vigor to undergo chromosome doubling.
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Abstract

Somatic chromosome numbers are given for the following Taraxacum species: T. pieninicum, 2n=16; T. dentatum, 2n=24; T. fascinans, 2n=24; T. mendax, 2n=40; T. subalpinum, 2n=24; T. telmatophilum, 2n=24; T. cyanolepis, 2n=24; T. fulgidum, 2n=24; T. gentile, 2n=24; and T. undulatum, 2n=24. Chromosome numbers from Poland are published for the first time for T. dentatum, T. fascinans, T. mendax, T. subalpinum, T. telmatophilum, T. cyanolepis, T. fulgidum, T. gentile and T. undulatum.
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