Giemsa C-banded karyotypes of diploid and tetraploidHordeum bulbosum (Poaceae)

The similar-looking basic genomes ofHordeum bulbosum (2x and 4x) have five rather similar metacentric, one submetacentric, and one satellited choromosome. C-banding patterns are characterized by one or two centromeric, or juxtacentromeric, small to larger bands in most chromosomes, by bands at the nucleolar organizers, by small or very small telomeric bands, and by the nearly complete lack of intercalary bands. Banding pattern polymorphism is widespread. Banding patterns supported by chromosome morphology enable identification of homologues, and discrimination between non-homologues inH. bulbosum (2x). The C-banded karyotype ofH. bulbosum (4x) supports an autopolyploid origin, but it was possible to identify only homologues of submetacentrics and SAT-chromosomes.     

Giemsa C-banded karyotypes inCapsicum (Solanaceae)

Giemsa C-banding is applied for the first time inCapsicum, allowing preliminary karyotype differentiation of six diploid species. Comparison of interphase nuclei and heterochromatic C-bands reveals striking differences between taxa and contributes to their taxonomic grouping. Therefore, C-banding appears to be a powerful tool for the cytogenetics and karyosystematics of the genus. Banding patterns are characterized by the omnipresence of centromeric bands and a variable number of smaller to larger distal bands, with the addition of intercalary bands in some cases. Satellites are always C-positive. Relationships between species and possible trends of karyotype evolution are discussed, with special reference to the origin of x = 13 from x = 12 and the increase of heterochromatin, regarded as advanced features.Chromosome studies inCapsicum (Solanaceae), III. For the first and the second part seeMoscone (1990, 1993).     

Variation of Giemsa C-band and fluorochrome banded karyotypes,and relationships inAllium subgen.Molium

The somatic karyotypes of 10 taxa belonging toAllium subgen.Molium (Liliaceae) from the Mediterranean area have been investigated using Giemsa C-band and fluorochrome (Hoechst, Quinacrine) banding techniques. A wide range of banding patterns has been revealed. InAllium moly (2n = 14),A. oreophilum (2n = 16) andA. paradoxum (2n = 16) C-banding is restricted to a region on each side of the nucleolar organisers and the satellites show reduced fluorescence with fluorochromes. The satellites are also C-banded and with reduced fluorescence inA. triquetrum (2n = 18), but two other chromosome pairs also have telomeric bands which are not distinguished by fluorochrome treatment. InA. erdelii (2n = 16) 4 pairs of metacentric chromosomes have telomeric C-bands while 2 pairs of telocentric chromosomes have centromeric C-banding. InA. subhirsutum (2n = 14),A. neapolitanum (2n = 28),A. trifoliatum subsp.hirsutum (2n = 14) andA. trifoliatum subsp.trifoliatum (2n = 21) chromosomes with long centromeres, consisting of a centromere and nucleolar organiser are positively C-banded on each side of the constriction. InA. subhirsutum banding is confined to the pair of chromosomes with this feature, whereas inA. neapolitanum one additional chromosome pair has telomeric bands and inA. trifoliatum there are varying numbers of chromosomes with centromeric and telomeric bands, depending on the subspecies.A. zebdanense (2n = 18) shows no C-bands. The banding patterns in this subgenus are compared with those recorded for otherAllium species and with the sectional divisions in the genus. Evidence from the banding patterns for allopolyploidy inA. trifoliatum subsp.trifoliatum andA. neapolitanum is discussed.     

Giemsa C-banded karyotypes of some diploidArtemisia species

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.     

Quantitative analyses of C-banded karyotypes,and systematics in the cultivated species of theScilla siberica group (Liliaceae)

Quantified C-band karyograms are presented for the related speciesScilla siberica, S. mordakiae, S. ingridae, S. amoena, andS. mischtschenkoana. Chromosome structure, banding style, and heterochromatin characters suggest a systematic grouping of two more closely related species pairs:S. siberica andS. mordakiae, S. ingridae andS. amoena; they are part of a larger aggregate, well separated fromS. mischtschenkoana. Four different heterochromatin fractions can be recognized inS. siberica and its relatives, but only two inS. mischtschenkoana. C-bands do not replace, but they are added to euchromatin. The particular origin and history of the cultivatedS. amoena and the triploidS. siberica cv. Spring Beauty appear to be responsible for their karyotype constancy, but chromosome conservatism obviously is genuine inS. mischtschenkoana. The banding data support the systematic grouping proposed on a morphological basis, and provide additional evolutionary evidence.Evolution ofScilla and Related Genera, IV.     

Giemsa karyotypes and their evolutionary significance inScilla bifolia,S. drunensis,andS. vindobonensis (Liliaceae)

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.Evolution ofScilla and Related Genera, II.Dedicated to Univ.-Prof. Dr.Elisabeth Tschermak-Woess on the occasion of her 60th birthday.     

Giemsa C-banded karyotypes of two subspecies ofHordeum brevisubulatum from China

C-banding patterns ofH. brevisubulatum subsp.brevisubulatum (2x) and subsp.turkestanicum (4x) had conspicuous telomeric C-bands in at least one chromosome arm with a minor difference in average band size between subspecies. Other conspicuous bands were few in number as in other taxa of the species complex. The C-banded area of the chromosomes was estimated to be 7 to 8 and 6 per cent, respectively. C-banding- and SAT-chromosome polymorphisms were observed in both subspecies. The latter and previous observations indicate that the number of SAT-chromosomes is a less reliable diagnostic character. Nucleolar organizer region polymorphisms were demonstrated through silver nitrate staining of nucleoli. C-banding patterns corroborated that tetra- and hexaploid cytotypes of subsp.turkestanicum form an autopolyploid series. Reliable identification ofH. brevisubulatum taxa based on cytological criteria should include the simultaneous use of C-banding patterns, and number and morphology of marker chromosomes.     

Giemsa C-banded karyotypes ofAllium ericetorum andA. kermesinum (Alliaceae)

The widely distributedAllium ericetorum and the local endemic of the Steiner Alps (Slovenia),A. kermesinum, are two closely related species of sect.Rhizirideum, whose main distinguishing character is perianth colour. To obtain further evidence for species separation, karyotype morphology and C-banding patterns were examined in 10 populations. The chromosome number was 2n = 16. In some populations ofA. ericetorum a B-chromosome occurred. Arm and satellite lengths and C-banding patterns were subjected to cluster analysis. Three different karyotype classes were observed and described. Karyotypes did not clearly discriminate between plants with different colours of perianth segments and therefore did not provide evidence for a taxonomic separation ofA. ericetorum and A. kermesinum. There is polymorphism in number and patterns of C-bands within the populations. No correlation between B-chromosomes and particular banding patterns was observed.     

Comparison of the Giemsa C-banded and N-banded karyotypes of twoElymus species,E. dentatus andE. glaucescens (Poaceae: Triticeae)

The karyotypes ofElymus dentatus from Kashmir andE. glaucescens from Tierra del Fuego, both carrying genomesS andH, were investigated by C- and N-banding. Both taxa had 2n = 4x = 28. The karyotype ofE. dentatus was symmetrical with large chromosomes. It had 18 metacentric, four submetacentric and six satellited chromosomes. The karyotype ofE. glaucescens resembled that ofE. dentatus, but a satellited chromosome pair was replaced by a morphologically similar, non-satellited pair. The C-banding patterns of both species had from one to five conspicuous and a few inconspicuous bands per chromosome. N-banding differentiated the chromosomes of the constituent genomes by producing bands in theH genome only. TheS genomes of both species were similar with five metacentric and two satellited chromosomes having most conspicuous C-bands at telomeric and distal positions. They resembled theS genome of the genusPseudoroegneria. TheH genomes had four similar metacentric and two submetacentric chromosomes. The seventhH genome chromosome ofE. dentatus was satellited, that ofE. glaucescens nonsatellited, but otherwise morphologically similar. The C-bands were distributed at no preferential positions. TheH genome ofE. dentatus resembles theH genomes of some diploidHordeum taxa.     

Heterochromatin and chromosome variation in cultivated species ofTulipa subg.Leiostemones (Liliaceae)

The chromosomes of several cultivatedTulipa species of subg.Leiostemones were examined in conventionally stained and C-banded preparations. The heterochromatin content varied from almost none to 45%. Several chromosome types were recognized with respect to chromosome morphology and heterochromatin distribution, and groups of species with common chromosome characteristics could be identified. These karyological relationships are discussed with respect to the groups formed on the basis of floral and bulb charateristics.     

B-Chromosomes inAllium flavum (Liliaceae) and some related species

B-Chromosomes ofAllium flavum, A. stamineum andA. carinatum were C-banded. InA. flavum different types of B's were found, one of them possessing a nucleolus organizer. In the B's ofA. flavum andA. stamineum the banding patterns resemble those found in the standard chromosomes. The B inA. carinatum is only terminally banded. InA. flavum chiasma localization in the B's appears to be dependent on C-band location, just as is the case in the A-chromosomes. An increase in B's was found to cause a small (but significant) increase in chiasma frequency in the PMC's. This may result from an alteration in the nucleotype by the B's.     

Heterochromatin and chromosome variation in cultivated species ofTulipa subg.Eriostemones (Liliaceae)

The chromosomes of several cultivatedTulipa species belonging to the subg.Eriostemones were examined using conventional staining and C-banding techniques. Most of the species have lightly banded chromosomes with heterochromatin content varying from nil to about 15%. The banding patterns of several taxa are described and discussed in regard to species relationships.     

Comparison of the Giemsa C-banded karyotypes of the three subspecies ofPsathyrostachys fragilis,subspp.villosus (2x),secaliformis (2x, 4x), andfragilis (2x) (Poaceae), with notes on chromosome pairing

The karyotypes of diploidP. fragilis subsp.villosus (2n = 2x = 14) and tetraploid subsp.secaliformis (2n = 4x = 28) were studied by Giemsa C- and N-banding, and AgNO₃ staining and compared with the karyotype of subsp.fragilis (2x). The complements of subsp.villosus and subsp.fragilis were similar, with 8 metacentric and 6 SAT-chromosomes, one metacentric and two submetacentric pairs, with small to minute, polymorphic, heterochromatic satellites. The complement of subsp.secaliformis on the whole agreed with a doubling of the complement of diploidP. fragilis, suggesting autopolyploidy. Only the presence of 12 nucleoli in interphases identified 6 SAT-chromosome pairs. In subsp.villosus one or two extra micronucleoli indicated a chromosome pair with very low nucleolusforming activity, bringing the number of SAT-chromosome pairs to 4. This number may be a characteristc ofPsathyrostachys. Besides very small, inconsistently observed bands, the C-banding pattern consisted of 0–3 small bands per chromosome at intercalary and terminal locations, and at NORs. The level of banding pattern polymorphism was low, but enough to indicate that the taxa are outbreeders. Similarities in chromosome morphology and C-banding patterns identified homology of all chromosomes of subsp.villosus, but for 12 pairs only in subsp.secaliformis. Between plants, reliable identification of homology and homoeology (subsp.secaliformis) was possible only for the SAT-chromosomes and the shortest metacentrics. Chromocentres were very small and the amount of constitutive heterochromatin was low. N-banding stained chromosomes uniformly. The basic karyotypes of theP. fragilis taxa were similar to those ofP. juncea, P. lanuginosa, andP. stoloniformis supporting a close relationship and the presence of a common genome, N. NORs had different nucleolus-forming activities. Meiotic analysis demonstrated a high level of bivalent pairing in the three taxa. A chromosomal rearrangement was suggested in subsp.villosus. The low multivalent frequency in subsp.secaliformis indicates the presence of a pairing regulation mechanism. The majority of chiasmata were interstitial. Pollen grain size discriminated between diploid and tetraploid taxa. The existence of a diploid cytotype of subsp.secaliformis is supported by pollen measurements of herbarium material.     

A survey of C-band patterns in chromosomes ofLilium (Liliaceae)

C-band patterns are described for 20Lilium spp. distributed across six sections. All species have a similar basic karyotype (n = 12) but C-bands differ markedly between them. The patterns are characterized by a dispersed scattering of thin intercalary bands as well as centric and NOR bands. Only one species,L. canadense, shows a clear equilocal pattern with intercalary C-bands occurring proximally in all of the longer chromosome arms. Comparing species, similar patterns are revealed forL. regale andL. sulphureum, forL. formosanum andL. longiflorum (all in sect.Leucolirion) and to a lesser extent forL. hansonii, L. martagon, andL. tsingtauense (sect.Martagon). The pattern forL. henryi (previously classed in sect.Sinomartagon) matches those ofL. regale andL. sulphureum quite well and its transfer to sect.Leucolirion is proposed. This is consistent with results from interspecies hybrids betweenL. henryi andL. regale (and related species) which are reportedly fertile. No other clear similarities in C-band patterns were seen across species. It seems that C-band patterns change rapidly inLilium and hence their usefulness in classification will be restricted to identifying closely related species.Dedicated to Prof.D. G. Catcheside on the 80th anniversary of his birth.     

Giemsa banded karyotypes,systematics, and evolution inAnacyclus (Asteraceae-Anthemideae)

Giemsa C-banding allows the differentiation of six, otherwise very similar karyotypes from the small genusAnacyclus. Banding style—with stable centromeric and nucleolar bands, and diverse specific banding patterns in distal chromosome segments—contributes significantly to generic demarcation and systematic grouping. The amount of banding corresponds to heterochromatic chromocentres and increases from perennials to annuals. Relationships with other nucleotype parameters and evolutionary mechanisms are discussed.First contribution of a series on Giemsa Banded Karyotypes, Systematics, and Evolution inAnthemideae (Asteraceae).     

Amounts of ribosomal DNA inAllium (Liliaceae)

Eight species ofAllium subgen.Allium sect.Allium have been studied at the cytological level by means of karyological analyses and at the biochemical level with regard to the proportions of ribosomal DNA. All the species have a basic genome of x = 8.A. sativum, A. commutatum, A. ampeloprasum, andA. vineale possess approximately 0.050% rDNA and two nucleolus organizer regions per basic chromosome set.A. sphaerocephalon andA. arvense have two nucleolus organizers, andA. amethystinum three nucleolus organizers per haploid (n = x) genome: the three species possess approximately 0.075% rDNA.A. acutiflorum has five nucleolus organizer regions per haploid genome and 0.121% rDNA. An attempt to relate these differences with functional and ecological characteristics indicates that evolutionary variation of rDNA proportions is not casual. Such data also can help to define systematic affinities and circumscribe infrageneric taxa.     

Infraspecific variation in C-banded karyotype and chiasma frequency inCucumis sativus (Cucurbitaceae)

Infraspecific cytogenetical variation was studied in a diverse collection of five non-cultivated and cultivatedCucumis sativus accessions. The individual chromosomes of different accessions could be identified by the C-banding pattern and chromosome measurements. About 40–50% of the genomic area are made up of heterochromatin inC. sativus. The non-cultivated accessions exhibit more heterochromatin and lower chiasma frequencies per pollen mother cell than cultivated accessions. There is infraspecific variation in C-banding pattern, karyomorphology and multinucleolate cells. The use of C-banding in infraspecific classification is discussed.     

Random arrangement of chromosomes inUvularia (Liliaceae)

Chromosome arrangement in interphase has been inferred from an analysis of the relative positions of the chromosomes and the chromosome arms in untreated haploid pollen grain metaphases ofUvularia grandiflora. The distances between centromeres forming the smallest possible circle were measured in 43 metaphases. The relative positions of the chromosomes did not differ significantly from randomness. Neither did similar-sized chromosome arms show any tendency to be next to each other. The results thus disagree both with the hypothesis ofComings (1968) that each chromosome occupies a definite position in the interphase nucleus and with the claim ofBennett (1982) that similar-sized chromosome arms lie next to each other.     

Insect and wind pollination inUrginea maritima (Liliaceae)

Three co-existing pollination mechanisms are found inUrginea maritima: insect-, wind-, and self-pollination. The flowers exhibit a typical insect-pollination syndrome; they offer abundant exposed nectar as well as pollen. Out of the many different visitors only a few could be regarded as pollinators:Apis mellifera, Polistes gallicus, andVespa orientalis. Wind pollination also occurs and generally is responsible for self-pollination.It is argued that the development of extra wind-pollination accompanied by partial self-incompatibility is an adaptation to increase pollination in an unfavourable season (August–September), when insects are scarce.     

Cytogenetical evidences for hybrid structure and origin of diploid and triploid shallots (Allium cepa var.viviparum,Liliaceae) from Dalmatia (Croatia)

Two viviparous strains of common onion (Allium cepa) denoted asAllium cepa var.viviparum (syn.Allium ×proliferum), traditionally cultivated in the seaside regions of Croatia were found to be diploid (2n = 2x = 16) and triploid (2n = 3x = 24), respectively. The triploid cultivated onion Ljutika has not been previously reported in Europe. Using Feulgen and Giemsa C-banding methods both karyotypes were shown to be of hybrid constitution. Results obtained in this work indicate that Dalmatian viviparous onions arose from spontaneous hybridization ofA. cepa withA. fistulosum.