Karyotype constancy and genome size variation in BulgarianCrepis foetida s. l. (Asteraceae)

Dimitrova, Dessislava; Ebert, Irma; Greilhuber, Johann; Kozhuharov, Stefan

doi:10.1007/bf00984369

Cited by 22 publications

(19 citation statements)

References 19 publications

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“…FISH revealed only two signals for 45S rDNA in interphase nuclei, and these were observed on almost the entire short arm of one submetacentric pair ( Figure 1C). CMA 3 + NORassociated heterochromatin has been observed on the short arm of a submetacentric pair in three Crepis foetida subspecies (2n = 10), in addition to smaller pericentromeric and intercalary dots revealed by Giemsa-C banding (Dimitrova et al, 1999). Guerra (1982) and Noguchi and Ohno (1989) described large C-bands on the short arm of submetacentric pairs in C. vesicaria and C. capillaris, respectively, in which this large heterochromatic block was associated with NOR, at least in C. capillaris.…”

Section: Resultsmentioning

confidence: 99%

A karyotypic study of three southern Brazilian Asteraceae species using fluorescence in situ hybridization with a 45S rDNA probe and C-CMA3 banding

2004

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The Asteraceae, one of the largest families of flowering plants, contains about 1,100 genera and 20,000 species, and is well known for its extensive karyotypic variation. In this study, conventional Feulgen staining, C-CMA 3 banding, and fluorescence in situ hybridization with a 45S rDNA probe were used to determine the chromosome number and the number and physical position of GC-rich heterochromatin and 45S rDNA sites in three Asteraceae weed species (Crepis japonica, Galinsoga parviflora and Chaptalia nutans). The three species exhibited karyotype differences in the chromosome number and shape, as a commom feature of Asteraceae. However, the 45S rDNA sites always occurred on the short chromosomal arms, associated with GC-heterochromatin. Althought of these differences, it suggests that commom features of plant karyotype are maintained.

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Section: Resultsmentioning

confidence: 99%

A karyotypic study of three southern Brazilian Asteraceae species using fluorescence in situ hybridization with a 45S rDNA probe and C-CMA3 banding

2004

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“…Feulgen densitometry was conducted on the Leitz MPV2 scanning cytophotometer (compare König et al 1987) and on the videobased Kontron CIRES (Cell Image Retrieval and Evaluation System, version 3.1) (Temsch et al 1998;Dimitrova et al 1999). Allium cepa "Frühstamm" root tips (2C=33.5pg) were used as reference for DNA content determination (compare Greilhuber and Ebert 1994).…”

Section: Methodsmentioning

confidence: 99%

Origin of facultative heterochromatin in the endosperm ofGagea lutea (Liliaceae)

et al. 2000

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SummaryFacultative heterochromatin occurs not only in certain animals in connection with sex determination but also in at least one plant genus, Gagea (Liliaceae s. str.), but here in the course of embryo sac development, fertilization and endosperm formation. The present contribution intends to provide undebatable photographic and cytometric evidence, previously not available, for the events in the course of which three whole genomes in the pentaploid endosperm nuclei of Gagea lutea become heterochromatinized. In this plant, embryo sac formation usually follows the Fritillaria type, i.e., the embryo sac is tetrasporic, and a '1 + 3 position' of the spore nuclei is followed by a mitosis in which the three chalazal spindles fuse and two triploid nuclei are formed. A triploid chalazal polar nucleus is derived from one of these, which contributes to the pentaploid endosperm. These nuclei in the chalazal part of the embryo sac show stronger condensation compared with the micropylar ones. The pycnosis of the triploid polar nucleus is maintained and even enhanced during endosperm proliferation, while the micropylar polar nucleus and the sperm nucleus maintain their euchromatic condition. The origin of the heterochromatic masses in the endosperm nuclei from the three chalazal genomes of the central cell is unambiguously evident from the distribution of heterochromatic chromosomes in the first endosperm mitosis and the following interphase.DNA content measurements confirm a 3:2 relationship of heterochromatic and euchromatic chromosome sets, which is usually maintained up to the cellularized endosperm. Pycnotic nuclei in the chalazal part of megagametophytes are characteristic for several embryo sac types, but Gagea spp. it is documented that such nuclei can take part in fertilization and endosperm formation.

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“…The knowledge that genome size is usually constant within the same taxonomic entity ( Greilhuber, 2005 ) but may vary tremendously even among closely related taxa ( Bennett and Leitch, 2005 ) provides a foundation for employing genome size as an important taxonomic marker. Indeed, this character has proven successful in resolving complex low-level taxonomies, delimiting species boundaries, and revealing cryptic taxa ( Dimitrova et al, 1999 ;Mahelka et al, 2005 ;Kron et al, 2007 ;Suda et al, 2007 ). Despite its potential taxonomic value, genome size has largely been neglected in the biosystematics of ferns in general (but see Bure š et al, 2003 ;Ebihara et al, 2005 ;Ekrt and Š tech, 2008 ;Ekrt et al, 2009 ), and in the D. carthusiana group in particular.…”

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Species boundaries and frequency of hybridization in the Dryopteris carthusiana (Dryopteridaceae) complex: A taxonomic puzzle resolved using genome size data

Ekrt

Holubova

Trávníček

et al. 2010

American J of Botany

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and 4 Institute of Botany, Academy of Sciences of the Czech Republic, Pr ů honice 1, CZ-252 43 Pr ů honice, Czech Republic• Premise of the study : Genome duplication and interspecifi c hybridization are important evolutionary processes that significantly infl uence phenotypic variation, ecological behavior, and reproductive biology of land plants. These processes played a major role in the evolution of the Dryopteris carthusiana complex. This taxonomically intricate group composed of one diploid ( D. expansa ) and two allotetraploid ( D. carthusiana and D. dilatata ) species in Central Europe. Overall phenotypic similarity, great plasticity, and the incidence of interspecifi c hybrids have led to a continuous dispute concerning species circumscription and delimitation.• Methods : We used fl ow cytometry and multivariate morphometrics to assess the level of phenotypic variation and the frequency of hybridization in a representative set covering all recognized species and hybrids.• Key results : Flow cytometric measurements revealed unique genome sizes in all species and hybrids, allowing their easy and reliable identifi cation for subsequent morphometric analyses. Different species often formed mixed populations, providing the opportunity for interspecifi c hybridization. Different frequencies of particular hybrid combinations depended primarily on evolutionary relationships, reproductive biology, and co-occurrence of progenitors.• Conclusions : Our study shows that genome size is a powerful marker for taxonomic decisions about the D. carthusiana complex and that genome size data may help to resolve taxonomic complexities in this important component of the temperate fern fl ora.

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Karyotype constancy and genome size variation in BulgarianCrepis foetida s. l. (Asteraceae)

Cited by 22 publications

References 19 publications

A karyotypic study of three southern Brazilian Asteraceae species using fluorescence in situ hybridization with a 45S rDNA probe and C-CMA3 banding

A karyotypic study of three southern Brazilian Asteraceae species using fluorescence in situ hybridization with a 45S rDNA probe and C-CMA3 banding

Origin of facultative heterochromatin in the endosperm ofGagea lutea (Liliaceae)

Species boundaries and frequency of hybridization in the Dryopteris carthusiana (Dryopteridaceae) complex: A taxonomic puzzle resolved using genome size data

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