Variation of Nuclear Dna Content in Helianthus Annuus (Asteraceae)

Michaelson, Martin J.; Price, H. James; Johnston, J. Spencer; Ellison, J. R.

doi:10.1002/j.1537-2197.1991.tb11416.x

Cited by 45 publications

(23 citation statements)

References 18 publications

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“…For example, H annuus (HA89) has the fourth lowest DNA content of the 19 species with 2n = 34 chromosomes (Sims & Price, 1985). Intraspecific variation in DNA content amongst cultivated varieties and inbred lines of H. annuus has also been described (Cavallini et al, 1986;Chandler, 1991;Michaelson et a!., 1991). To what extent different amounts of heterochromatin may be involved in this DNA content variation remains to be elucidated, but from our results we know that HA89 has little constitutive heterochromatin, which is confined to small bands in the centromeric areas and secondary constrictions.…”

Section: Discussionmentioning

confidence: 99%

Chromosomal differentiation in Helianthus annuus var. macrocarpus: heterochromatin characterization and rDNA location

et al. 1996

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The 2n = 34 chromosomes of the inbred line HA89, and the Flamme and Mirasol hybrids of Helianthus annuus var. macrocarpus possess centromeric heterochromatin as established by Giemsa C-banding. This heterochromatin can not be differentiated by fluorochromes such as DAPI or Chromomycin A3, with selective affinity for specific DNA base pairs. This situation probably results from either a balanced AT/GC composition of the involved repeat or the existence of alternating repetitive sequences of opposite base pair composition in these heterochromatic areas. However, there is also heterochromatin associated with the secondary constrictions on three pairs of chromosomes. This heterochromatin appears to be GC-rich according to its response to the fluorochrome treatments, thus indicating heterochromatin heterogeneity in H. annuus. Silver staining reveals the existence of active NORs associated with these secondary constrictions. In situ hybridization with an rDNA probe confirms these results and makes the existence of other inactive rDNA sites unlikely. These results are relevant to evolutionary and breeding studies on sunflowers.

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Section: Discussionmentioning

confidence: 99%

Chromosomal differentiation in Helianthus annuus var. macrocarpus: heterochromatin characterization and rDNA location

et al. 1996

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“…The DNA C-value for a species is the amount of nuclear DNA in the unreplicated haploid genome of a gamete, and it tends to be characteristic of a taxon and quite constant within a species (Swift 1950). However, since the beginning of the 1980s the number of studies showing significant intraspecific variation in genome size has continued to increase and the original view of species-specific constancy has been questioned (Michaelson et al 1991;Reeves et al 1998;Schmuths et al 2004). Numerous studies have shown variation in C-values in many plant species ranging from a few to as high as 32% (for example, in Arabidopsis thaliana (L.) Heynh.…”

Section: Introductionmentioning

confidence: 99%

“…Numerous studies have shown variation in C-values in many plant species ranging from a few to as high as 32% (for example, in Arabidopsis thaliana (L.) Heynh. and Helianthus annuus L. respectively) (Michaelson et al 1991;Schmuths et al 2004;Doležel and Bartos 2005). In several cases these findings have been rejected on reinvestigation using an improved technical approach (Greilhuber 2005).…”

Section: Introductionmentioning

confidence: 99%

Genome size variation in Chenopodium quinoa (Chenopodiaceae)

et al. 2011

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The extent and significance of intraspecific genome size variation were analysed in quinoa (Chenopodium quinoa Willd.), a pseudocereal important for human consumption in the Andean region of South America. Flow cytometry, with propidium iodide as the DNA stain, was used to estimate the genome size of 20 quinoa accessions from Ecuador, Peru, Bolivia, Argentina, Chile and the USA. Limited genome size variation was found among the analysed accessions. The differences between the accessions were statistically significant but the maximum inter-accession difference between the populations with the largest and the smallest genome reached only 5.9%. The largest genome was found in population C4 from Chile (mean 3.077 pg/2C) and the smallest in the Peruvian population P2 (mean 2.905 pg/2C). The variation was not correlated with collection site; however, the quinoa accessions analysed in this study belonged to three distinct geographical groups: northern highland, southern highland and lowland.

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“…Distinct authors also evidenced intraspecific differences in 2C DNA content in soybean (Graham et al 1994, Rayburn et al 1997, sunflower (Michaelson et al 1991), pea (Arumuganathan and Earle 1991) and maize (Rayburn et al 1989). In some cases, these results were correlated with environmental gradients or development conditions (Doležel andBartoš 2005, Knight et al 2005).…”

Section: Flow Cytometrymentioning

confidence: 98%

Karyotype and nuclear DNA content of Psychotria ipecacuanha: a medicinal species

Rossi

Clarindo

Oliveira³

2008

CYTOLOGIA

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Summary Psychotria ipecacuanha, ipecac, is a perennial, medicinal herb that grows in clusters in the understory of humid and shady areas of the Brazilian Atlantic and Amazon forests. Cytogenetic studies performed in this species have reported 2nϭ22 chromosomes, with limited karyotypic information. The present study was conducted in order to apply cytogenetic and flow cytometric tools in samples of ten ipecac populations, five from the Atlantic and five from the Amazon forest, with the purpose of characterizing their karyotype and measuring their 2C DNA content. The flow cytometry analyses evidenced two groups with distinct DNA amounts: MOZ population with 2Cϭ1.24 pg and GUA, TVI, TLM, VRB, RAP, MAN, RVE, BBU and PRA populations with 2Cϭ2.05 pg. Metaphasic chromosomes obtained from root apical meristems of GUA, TLM and TVI showed a karyotype consisting of 11 chromosome pairs, 4 metacentric (4, 5, 8 and 9) and 7 submetacentric (1, 2, 3, 6, 7, 10 and 11), with lengths varying from 3.97 to 2.53 mm. The secondary constriction was identified in the long arm of chromosome 6. Cytogenetic characterization also reveled that each chromosome pair 2-3; 4-5; 6-7; 8-9 and 10-11 is cytogenetically similar, with regard to total length, short and long arm size, and chromosomic class, suggesting that this species might be a tetraploid plant.

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Variation of Nuclear Dna Content in Helianthus Annuus (Asteraceae)

Cited by 45 publications

References 18 publications

Chromosomal differentiation in Helianthus annuus var. macrocarpus: heterochromatin characterization and rDNA location

Chromosomal differentiation in Helianthus annuus var. macrocarpus: heterochromatin characterization and rDNA location

Genome size variation in Chenopodium quinoa (Chenopodiaceae)

Karyotype and nuclear DNA content of Psychotria ipecacuanha: a medicinal species

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