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Karyosystematic studies on threeCrepis species (Asteraceae) endemic to Greece
Abstract
This work examines the cytogeographical distribution, the morphological characters, and the karyotypes of threeCrepis species endemic to Greece (C. sibthorpiana, C. incana, andC. heldreichiana). C. sibthorpiana is diploid (2n = 2x = 8),C. incana is diploid (2n = 2x = 8) and tetraploid (2n = 4x = 16, 17), andC. heldreichiana is always dekaploid (2n = 10x = 40). The Giemsa positive bands, usually pairs of dots, are mainly centromeric inC. incana, while they are terminal inC. sibthorpiana (on the short arm of all chromosomes) and inC. heldreichiana (on both arms of all chromosomes). Intercalary C-bands are scarce and usually variable within karyotypes, individuals, and species. The most variable karyotype both in Feulgen and Giemsa preparations is that ofC. incana, in which also supernumerary chromosomes were observed, which are polysomic to standard set members. On the basis of morphological and karyological data the evolutionary relationships among the threeCrepis taxa are discussed.
... Most of the micromorphological, anatomical and cytogenetical studies conducted in Crepis have concentrated on common species, with some work having been interested in endemic species (Kamari et al. 1991, Kamari 1992, Enke 2009, Enke et al. 2011, Siljak-Yakovlev and Peruzzi 2012. To our knowledge, except the chromosome counting of C. dioritica (2n = 8, Davis et al. 1988) in Turkey, no micromorphological, anatomical and cytogenetic studies have been reported for Turkish endemic species of Crepis. ...
... Crepis macropus is a diploid species with 2n = 2x = 8 chromosomes. This species has the same chromosome number with the members of the section Berinia such as C. turcica, C. merxmuerlleri, C. sibthorpiana, C. sonchifolia (Nazarova 1984, Kamari et al. 1991, Kamari 1992, Constantinidis et al. 2002, Enke 2008). There is a minor difference in the chromosome morphology between C. macropus and C. turcica (Kamari et al. 1991). ...
In the present study, the micromorphological structure of achene, pappus and style using scanning electron microscope (SEM), stomatal characteristics, anatomy of stem and achene together with chromosome number and nuclear DNA content of the Turkish endemic Crepis macropus Boiss. & Heldr. are provided in order to expand knowledge of its taxonomy. The SEM studies in this species show that dense spiny cells are found on the achene surface, the pappus bristle has 3–5 spikes and the style possesses slender papillae. The stem structure is composed of epidermis, collenchyma, parenchymatous cortex and pith. The species has anomocytic stomata in both the upper and the lower surface of the leaves. The pericarp of the achene is mainly composed of several layers of sclerenchymatous cells. In this species, the chromosome number is 2n = 2x = 8, karyotype consists of two submetacentric and six subtelocentric chromosomes and nuclear DNA content (2Cvalue) is 12.96 pg. These data are presented here for the first time and their taxonomic values are discussed.
... Even before Babcock published his extensive work on karyotype evolution in the genus (Babcock, 1947a,b), Crepis has been a popular object of cytological studies (e.g. Hollingshead, 1930;Tobgy, 1943;Sherman, 1946 Kamari, 1992;Dimitrova & Greilhuber, 2000). ...
... Sources for 1C-values taken from literature are given in the table. Chromosome numbers were taken from Babcock (1947a,b) and Kamari (1992). Information on life form was taken also from Babcock (1947a,b) as well as distributional and habitat information. ...
In 1947 Babcock published his widely acknowledged monograph of the genus Crepis L. including a sectional classification of the species as well as extensive hypotheses about character evolution. To reinvestigate Babcock's evolutionary hypotheses and the generic delimitation of Crepis L. a phylogenetic analysis was conducted using ITS and chloroplast matK sequence data. The results revealed Crepis L. to be polyphyletic. A monophyletic clade including Central Asian and North American species of Crepis sect. Ixeridopsis is clearly isolated from Crepis s.str. and, as also supported by additional morphological evidence, needs to be transferred to the genus Askellia Weber (1984). A second clade comprising the genera Lapsana L. and Rhagadiolus Juss. as well as a statistically strongly supported clade of several Crepis species is sister to a third clade: the monophyletic Crepis s.str. Within Crepis s.str. the molecular data does not support Babcock's sectional delimitation which is mainly based on his hypotheses about karyotype evolution. Hence, morphological and karyological characters are re-assessed with regard to the molecular phylogeny.
... This genus is known as a model for the study of evolution and systematics of the flowering plants due to the low mitotic chromosome numbers encountered in the mostly diploid species, ranging from 2n = 6 to 2n = 12. Moreover, most Crepis species are diploid, and numerous chromosomal studies have been conducted up to now on the genus (Babcock 1947a, b;Siljak-Yakovlev & Cartier 1982;Kamari 1992;Dimitrova & Greilhuber 2000, 2001Enke et al. 2015;Inceer et al. 2018a). A decreasing tendency in the base number x (6→3) is distinct in diploid species of the genus (Babcock 1947a;Dimitrova & Greilhuber 2000). ...
In this study, we report genome size (C-values) estimated using flow cytometry
for 18 taxa of Asteraceae from Turkey, 17 of which are here assessed for the first
time. The studied taxa belong to the genera Achillea (one species), Anthemis (one
subspecies), Tanacetum (four taxa) and Crepis (12 taxa). Additionally, chromosome
numbers of nine taxa of Crepis are provided, four counts being new reports and the
remainder confirming previous data. The 2C-values of the studied taxa range from
2.08 to 11.06 pg, which represent more than fivefold variation. The systematic and
evolutionary significance of genome size is discussed within the framework of the
results obtained in this study.
... Paired t-tests have revealed similarities among the three karyotypes. Especially the similarity between TCL of the diploid F. epirotica 2n = 24 and F. montana 2n = 18 reinforces the hypothesis, apart from the secondary constrictions, that the second species has derived after successive chromosomal reconstructions and Robersonian-fusions. Less similar indices of TCL between F. montana 2n = 2x = 18 and F. montana 2n = 3x = 27 can also be explained since it is known that polyploidy usually comes with gene loss and genome amount reduction (Kamari 1992, Leitch and Bennett 2004, Adams and Wendel 2005, Buggs et al. 2009). Another proof for gene loss, is the fact that the triploid cytotype of F. montana has the lower price of THL. ...
Fritillaria Linnaeus, 1753 (Liliaceae) is a genus of geophytes, represented in Greece by 29 taxa. Most of the Greek species are endemic to the country and/or threatened. Although their classical cytotaxonomic studies have already been presented, no karyomorphometric analysis has ever been given. In the present study, the cytological results of Fritillariamontana Hoppe ex W.D.J. Koch, 1832 group, which includes Fritillariaepirotica Turrill ex Rix, 1975 and Fritillariamontana are statistically evaluated for the first time. Further indices about interchromosomal and intrachromosomal asymmetry are given. A new population of Fritillariaepirotica is also investigated, while for Fritillariamontana, a diploid individual was found in a known as triploid population. Paired t-tests and PCoA analysis have been applied to compare the two species.
... Crepis heldreichiana is an endemic species of S Peloponnisos, which occurs on the higher altitudes of the two main mountains, Taigetos and Parnonas. Babcock (1947a, b), the main investigator of the genus Crepis, counted the chromosome number 2n = 41, while Iatrou (1986) and Kamari (1992) refer 2n = 40. The latter author, using additionally C-banding technique, substantiate that the species is decaploid and polyploid, with 2n = 10x = 40 chromosomes. ...
Abstract
Kamari, G., Blanché, C. & Siljak-Yakovlev, S. (eds): Mediterranean chromosome number
reports – 24. — Fl. Medit. 24: 273-291. 2014. — ISSN: 1120-4052 printed, 2240-4538 online.
This is the twenty-four of a series of reports of chromosomes numbers from Mediterranean
area, peri-Alpine communities and the Atlantic Islands, in English or French language. It comprises contributions on 21 taxa: Hymenonema from Greece by E. Liveri, P. Bareka & G. Kamari (Nos 1824-1825); Fritillaria from Turkey by Mine Koçyiğit, N. Özhatay, U. Rastgeldi & E.
Kaya (Nos 1826-1836); Hieracium from Sicily by E. Di Gristina, G. Domina & A. Geraci (No 1837); Bellevalia and Leopoldia from Tunisia by A. Troia, G. Domina & V. Spadaro (Nos 1838-1839); Bubon, Centaurea, Crepis, Rindera and Scaligeria from Greece by Ch. Kyriakopoulos, P. Bareka & G. Kamari (Nos 1840-1844).
... CMA/DAPI banding has been widely used for angiosperms to identify heterochromatic bands with regard to their highly repeated DNA composition. The general patterns of band numbers and heterochromatin amounts can be conserved at the generic level (Galasso et al. 1997;Moscone et al. 1996;Marcon and Guerra 2005) or can be variable (Miranda et al. 1997;Guerra 2000;Fregonezi et al. 2006), as found here in the ''Xanthocephalum group'' and in other Asteraceae (Kamari 1992;Cerbah et al. 1995;D'Amato 2000;Dimitrova and. Greilhuber 2000;Ruas et al. 2000;Fregonezi et al. 2004;Garcia et al. 2009). ...
Fourteen North American members of the “Xanthocephalum group” were studied by classical and molecular cytogenetics. Location and number of rDNA sites were determined by FISH. For the 5S rDNA, a probe was obtained from Prionopsis ciliata. Most species were diploid (2n = 12), although Isocoma menziesii, Grindelia hirsutula, G. robusta, both varieties of G. stricta, and one population of G. camporum were tetraploid (2n = 24). Diploid Grindelia and Prionopsis ciliata were 5m + 1sm, tetraploids 10m + 2sm, except G. hirsutula (8m + 4sm), and Isocoma and Olivaea 6m + 2sm and 3m + 3sm, respectively. Most species had satellites on the short arms of m pairs: two in tetraploids and P. ciliata and one in diploids. Satellites were associated with two CMA+/DAPI− bands in diploid species and four bands in tetraploids and in P. ciliata. rDNA loci (two in diploids to four in tetraploids) may be indicative of ploidy level. Grindelia tetraploids could have originated recently by autopolyploidy. Chromosome duplication was followed by modifications in the genome structure, resulting in higher heterochromatin amounts not associated with NORs. There is only one 5S site per basic genome in para or pericentromeric regions. Although not always large, chromosome variation has accompanied the evolutionary divergence of the taxa studied.
Many recent karyological and karyosystematic studies have made successful attempts to incorporate not only chromosome counts, but also more detailed data on karyomorphology, chromosome banding, interphase nuclear organization, and DNA hybridization tests. They employ methods which have been or are being developed in a limited number of karyologically well-known genera such as Vicia, Allium, or Secale. Especially the banding methods which use dyes specific to DNA base pairs, partly combined with in situ hybridization techniques, now become applicable to a wider range of organisms. They undoubtedly prove to be most useful in comparative systematic studies. In the near future, this approach most probably will succeed to fill the gap between classical karyological studies which use various methods of microscopy and modern DNA sequencing.
Ten populations ofCrepis foetida from Bulgaria belonging to the three subspeciesfoetida, rhoeadifolia, andcommutata were analyzed karyologically using haematoxylin staining, Giemsa C-banding, fluorochrome banding, Ag-NOR staining, Feulgen cytophotometry (scanning densitometry and video-based image analysis), and propidium iodide flow cytometry. The quantitatively-evaluated karyotype structure was similar among all populations, with minor variation in a few intercalary sites only and in the amount of NOR-associated heterochromatin (satellites). In contrast to the karyotypic constancy the genome size ofC. foetida subsp.commutata was about 10% lower than those of the other two subspecies, which had similar genome sizes. The genome size measurements using three different methods resulted in highly correlated data. The genome size difference adds some weight to previous taxonomic opinions treatingC. foetida subsp.commutata at species level, asC. commutata.
The amounts of nuclear DNA and constitutive heterochromatin have been determined in 18 species of the Scilla bifolia group. and in the less closely related. S. messeniaca and S. siberica. Together with morphological criteria these data allow to reconstruct the pathways of chromosome evolution in the S. bifolia group at the diploid level with considerable accuracy. A progressive decrease of the DNA content by a factor of 0.5 occurred during the evolution from primitive yellow-seeded (S. kladnii: 1C = 8.6 pg) to advanced black-seeded species (e.g. S. luciliae: 1C = 4.3 pg). Grey- and brown-seeded species correspond to intermediary evolutionary stages and have intermediate DNA contents. 14 of 18 species have low amounts of heterochromatin (appr. 4%) irrespective of DNA content. However, two separate evolutionary side-branches are characterized by the accumulation of C-band material (3 yellow-seeded and 1 black-seeded species). The data suggest that an incipient DNA increase due to heterochromatin addition occurred in both instances. Further speciation in the yellow-seeded branch was accompanied by a decrease of total DNA despite of an increase in C-band content.—DNA contents once more establish the close relationship of the S. nivalis subgroup with the taxa formerly classified under Chionodoxa, viz. the S. luciliae subgroup.— The systematic position of S. messeniaca (x = 9) next to the S. bifolia group, previously suggested for reasons of morphology and chromosome number, is now supported by the DNA amount (1C = 10.7 pg). S. siberica (x = 6) as a remote relative contains considerably more DNA (1C = 31.7 pg).
Although Giemsa C-banding techniques have been used extensively for assaying cereal heterochromatin, a more specific technique for analyzing cereal heterochromatin has been developed recently with the isolation of DNA sequences present in heterochromatin and their employment in in situ hybridization to cereal chromosomes. A number of triticales were examined for the occurrence of modified rye chromosomes using the in situ hybridization technique. With a heterogeneous sequence probe the amount of rye heterochromatin appears to be relatively constant in wheat backgrounds but when a specific sequence probe was employed variation was observed. Whether this variation reflects polymorphism in rye or whether it is a result of adaption of the rye genome to coexistence with the wheat genome in triticales is discussed. - The triticale Rosner was examined in detail and it was established that the rye chromosome 2R had been replaced by the wheat chromosome 2D.
Detailed C-banded karyotypes of eight diploidArtemisia species from three different sections are reported together with preliminary observations on three additional related diploid species. In the majority, the overall amount of banding is relatively low. Bands are mostly confined to distal chromosome regions; intercalary banding is virtually absent and centromeric heterochromatin is also scarce. With the exception ofA. judaica there is in general great uniformity in karyotype structure but considerable interspecific variation in total karyotype length (and hence DNA content) ranging from 44 µm inA. capillaris (2n = 18) to 99 µm inA. atrata (2n = 18).A. judaica (2n = 16; total karyotype length 97 µm) was distinguished by its karyomorphology, with one large non-banded metacentric chromosome pair and 7 pairs of smaller terminally banded meta- or submetacentric chromosomes.
Quantitatively evaluated C-banded and conventional karyograms are presented for the related speciesScilla bifolia subsp.danubialis
Speta,S. drunensis (Speta)Speta, andS. vindobonensis
Speta. On the basis of banding patterns and karyotype structureS. bifolia subsp.danubialis (2n = 18, 2×) andS. drunensis (2n = 36, 4×) are quite similar, whileS. vindobonensis (2n = 18, 2×) is entirely different. There is a moderate degree of karyotypic variation withinS. bifolia subsp.danubialis andS. drunensis. However, inS. vindobonensis karyotypes and banding patterns are almost completely stable over a geographical range of about 500 km. The present results confirm the recent taxonomic separation ofS. vindobonensis fromS. bifolia, and suggest a considerable phylogenetic distance between these two diploid species. The results are discussed with reference to the morphological characters of the species and their geographical distribution.
Quantitatively evaluated C-banding karyograms are presented forAllium carinatum, A. carinatum ssp.pulchellum, andA. flavum of the sectionCodonoprasum
Reichenb. Accurate measurements revealed that constitutive heterochromatin (C-bands) is probably additional chromosomal material. The distribution of the C-heterochromatin follows the principle of the equilocal heterochromatin-distribution byHeitz (1933). Furthermore, the pattern shows a relationship to the relative arm-length of the chromosomes in the karyotype. Fluorochrome banding revealed various heterochromatintypes. The C-band patterns ofAllium cupani (sect.Scorodon
Koch) andA. vineale (sect.Allium), which are also rich in heterochromatin, are described.
Derived telocentric chromosomes in Nigella doerfleri have pairs of Giemsa staining dots at their terminal centromeres which appear in size and behaviour to be identical with the centromeric dots of their submetacentric homologue. The telocentric chromosomes are stable and therefore their centromeres are functional and probably complete. That the centromeres also possess centromeric dots indicates that the dots represent essential components of the centromere, a conclusion which supports the contention that they are kinetochores.