Karyotype analysis in someVernoniaspecies (Asteraceae) from South America
18
Citation
17
Reference
10
Related Paper
Citation Trend
Abstract:
SUMMARYThe somatic chromosomes of eight Vernonia species (Asteraceae) from Brazil, Paraguay and Argentina were analyzed. First chromosome counts are presented for V. coriacea Less. (2n=32 = 20m + 10sm + 2st), V. dura Mart, ex DC. (2n=32 = 22m + 10sm), V. eriolepis Gardn. (2n=32 = 22m + 8sm + 2st), V. grandiflora Less. (2n=64 = 50m + 14sm) and V. onopordioides Baker (2n=32 = 18m + 2m-sm + 10sm + 2st). Besides, the chromosome numbers of V. brevifolia Less. ((2n=32 = 22m + 10sm) and V. sellowii Less. (2n=62 = 40m + 20sm + 2st) are also confirmed. The number found in V. saltensis Hieron (2n=64 = 48m + 16sm) support the occurrence of two cytotypes within the species, one diploid (2n=32) and the other tetraploid (2n=64). The eight species revealed certain differences between their karyotypes principally in formula, total length and asymmetry level, which coincides with earlier studies for South American taxa. Satellites were commonly found on submetacentric or subtelocentric pairs, being also variable in morphology and location. Chromosomal data here reported and the already available for the genus indicate that the evolution of Vernonia have been followed for a decrease in number and size of the chromosomes.Keywords:
Chromosome number
Cytogenetic characterization by karyotyping and determination of DNA content by flow cytometry of five species of Chrysolaena (Vernonieae, Asteraceae) was performed. This is the first study of nuclear DNA content realized in the genus. The 2C-values were compared with the ploidy level and the total karyotype length (TKL) of each species. Mitotic analysis revealed a base chromosome number x = 10 for all entities and different ploidy levels, from diploid (2n = 2x = 20) to octoploid (2n = 8x = 80). All species showed bimodal karyotypes composed of metacentric and submetacentric chromosomes. The average chromosome size (ML) varied from 1.86 μm to 2.70 μm, while the TKL ranged from 18.65 μm to 80.55 μm. The intrachromosomal asymmetry index (A1) varied from 0.27 to 0.38, while the interchromosomal asymmetry index (A2) ranged from 0.19 to 0.25. A new cytotype is reported for the first time for C. propinqua. Accessory chromosomes found in C. verbascifolia, C. cognata, C. flexuosa, and C. propinqua are also reported as new.
Chromosome number
Nuclear DNA
Cite
Citations (8)
The chromosome number of 10 species and karyotypes of 9 species of them in the genus Caragana from China were analyzed in this paper,and the results are as follows:C.roborovskyi,2n=16=10m(2SAT)+6sm;C.erinacea,2n=16=10m+6sm;C.densa,2n=16=10m(2SAT)+6sm;C.acanthophylla,2n=16=12m+4sm;C.stipitata,2n=16=10m+6sm;C.opulens,2n=16=12m(2SAT)+4sm;C.leucophloea,2n=32=22m(4SAT)+10sm;C.camilli-schneideri,2n=32=20m(4SAT)+12sm,C.tragacanthoides,2n=32=20m(2SAT)+10sm+2st+2B.For two populations of C.licentiana,only chromosome numbers are reported here,both with 2n=4x=32,being tetraploid.From the results we inclined to suppose that the karyotype of chromosomes in Caragana is not so much differentiated,and if differentiated it always follows by some morphological characters.The diploid and tetraploid are the main ploidy level of this genus,with 2n=16(diploid)or 2n=32(tetraploid).Triploid was found only in C.sinica,and hexaploid was seen only in C.ussuriensis.Those species with diploid chromosomes mostly are pinnate-leaved,and are mainly distributed in Estern Asia where probably is the genus' ancestral areal,but those species with tetraploid chromosomes are majorly with digitate leaflets,and incline to adapt to desert areas in Northwestern China.
Chromosome number
Caragana
Cite
Citations (0)
Karyotype studies were performed in 18 populations of eight Helichrysum species in Iran. Those species showed chromosome numbers of 2n = 2x = 14; 2n = 4x = 24, 28 and 32; 2n = 6x = 36; 2n = 7x = 42; 2n = 8x = 48; 2n = 9x = 54; and 2n = 10x = 60. The chromosome numbers of H. davisianum, H. globiferum, H. leucocephalum and H. oocephalum are reported here for the first time. New ploidy levels are reported for H. oligocephalum (2n = 4x = 24) and H. plicatum (2n = 4x = 32). The chromosomes were metacentric and submetacentric. An ANOVA among H. globiferum and H. leucocephalum populations showed significant differences for the coefficient of variation for chromosome size, total form percentage and the asymmetry indices, indicating that changes in the chromosome structure of Helichrysum species occurred during their diversification. Significant positive correlations among the species and populations studied, in terms of the total chromosome length, lengths of the short arms and lengths of the long arms, indicate that these karyotypic features change simultaneously during speciation events. The genome sizes of Helichrysum species are reported here for first time. The 2C DNA content ranged from 8.13 pg (in H. rubicundum) to 18.4 pg (in H. leucocephalum and H. davisianum). We found that C-value correlated significantly with ploidy level, total chromosome length, lengths of the long arms and lengths of the short arms (p<0.05), indicating that changes in chromosome structure are accompanied by changes in DNA content.
Genome size
Chromosome number
Cite
Citations (10)
The chromosome numbers and karyomorphology of 32 accessions are examined, representing 12 species of Anaphalis DC. (Asteraceae) from the Hengduan Mountains of south-western China, which is most likely the biologically richest temperate region in the world. A total of 11 species are newly reported, and the highest chromosome number, 2n = 84, was observed in the Helichrysum–Anaphalis–Pseudognaphalium group for the first time. Within Anaphalis, the basic number x = 14 was confirmed. Only two species (A. flavescens and A. pachylaena) are diploid with 2n = 28. Tetraploidy is observed in seven species. Diploid–polyploid complexes are found in A. aureopunctata, A. bicolor, and A. nepalensis, especially for A. nepalensis with a series of polyploidy levels from di-, tetra-, to hexaploid. In addition to the tetraploid origin of the genus, a second polyploidisation is suggested as the predominant event in the chromosome evolution of Anaphalis from the Hengduan Mountains. The karyotypes of all observed samples are 2A or 2B, except for one population of A. bicolor as 1B according to Stebbins' asymmetry classification of karyotypes. The asymmetry index (AI) values change from 1.49 to 3.65. However, there is no evidence of association between chromosome evolution (i.e. polyploidy frequency and karyotype variation) and the altitudes in Anaphalis.
Chromosome number
Cite
Citations (5)
Chromosome numbers and karyotypes of Corylopsis glabrescens and C. gotoana in the Hamamelidaceae were investigated. Corylopsis glabrescens was diploid with 2n=24=14m+8sm+2st, while C. gotoana was tetraploid with 2n=48=36m+8sm+4st. The karyotype of the diploid C. glabrescens was different from that of the diploid C. pauciflora previously reported in Japan, suggesting a heterogeneous origin of the two species. The karyotype of the tetraploid C. gotoana seemed to share a homogeneous karyotype composition with the hexaploid C. spicata previously reported in Japan.
Chromosome number
Cite
Citations (1)
SUMMARYThe somatic chromosomes of eight Vernonia species (Asteraceae) from Brazil, Paraguay and Argentina were analyzed. First chromosome counts are presented for V. coriacea Less. (2n=32 = 20m + 10sm + 2st), V. dura Mart, ex DC. (2n=32 = 22m + 10sm), V. eriolepis Gardn. (2n=32 = 22m + 8sm + 2st), V. grandiflora Less. (2n=64 = 50m + 14sm) and V. onopordioides Baker (2n=32 = 18m + 2m-sm + 10sm + 2st). Besides, the chromosome numbers of V. brevifolia Less. ((2n=32 = 22m + 10sm) and V. sellowii Less. (2n=62 = 40m + 20sm + 2st) are also confirmed. The number found in V. saltensis Hieron (2n=64 = 48m + 16sm) support the occurrence of two cytotypes within the species, one diploid (2n=32) and the other tetraploid (2n=64). The eight species revealed certain differences between their karyotypes principally in formula, total length and asymmetry level, which coincides with earlier studies for South American taxa. Satellites were commonly found on submetacentric or subtelocentric pairs, being also variable in morphology and location. Chromosomal data here reported and the already available for the genus indicate that the evolution of Vernonia have been followed for a decrease in number and size of the chromosomes.
Chromosome number
Cite
Citations (18)
Abstract The description of the karyotype features and idiogram in Grindelia squarrosa (Pursh) Dunal (Asteraceae), an invasive plant in Romania, are reported here for the first time. The diploid chromosome number is 2n=2x=12, in agreement with the data published for the other species of the genus. The karyomorphological data show that the complements of the studied genotypes have small chromosomes (mean chromosome length is X̅±SE=2.56±0.10 μm, and mean length of haploid complements is X̅±SE=15.33±0.69 μm, with a range of variability comprised between 12.87-17.51 μm). The karyotypes are made up of six pairs of metacentric and submetacentric chromosomes, with an identical formula of the diploid complement: KF=2n=12=8m+ 2sm + 2sm-SAT. Satellites are located on the short arms of the chromosomes of pair III. The karyotypes show a relatively high level of intra-specific uniformity as well as similar symmetry patterns (R=1.29-1.53; TF%=38.78-41.57%; AsI%=54.54-57.61%; A1 = 0.24- 0.32; A2=0.08-0.16), belonging to 1A and 2A classes of symmetry. The small size of the chromosomes, the presence of only two chromosome morphometric types, and the preponderance of metacentrics confer a relatively high degree of symmetry to the karyotypes studied.
Chromosome number
Cite
Citations (3)
Chromosome numbers and karyotypes of 8 species of Saussurea, Pertya and Tricholepis from Hengduan Mountains with neighborhood were studied. The chromosome numbers and karyotype were reported firstly for Pertya berberidoides (2n=2x=32=28m+4sm), Tricholepis furcate (2n=2x=32=16m+16sm), Saussurea dschungdienensis (2n=2x=30=30m+Bs), S.likiangensis (2n=2x=32=26m+6sm), S.retroserrata (2n=2x=32=14m+18sm), and S.peduncularis (2n=2x=36=26m+10sm). The chromosome numbers and ploidy of S.hieracioides with 2n=4x=64=30m+34sm and S.deltoidea with 2n=2x=34=22m+12sm are consistent with previously report. All species have type 2B karyotype asymmetry, except for Saussurea dschungdienensis and Pertya berberidoides having type 1B. B chromosome was first discovered in Saussurea dschungdienensis. The results showed that the genus Saussurea and the tribe Mutisieae have a wide range of chromosome numbers and obvious aneuploidy. In addition, only diploid and tetraploid were found in Saussurea from Hengduan Mountains, and polyploidization might have played a minor role in the chromosomal evolution of the Saussurea in the Hengduan Mountains.
Tribe
Chromosome number
Cite
Citations (1)
Morpho-criteria, karyotype analysis, chromosome number and ploidy levels were studied for three mulberry varieties. Mysore local and RFS-175 is diploid with 2n=28 and BC2-59 is triploid with 2n=42 somatic chromosomes numbers respectively. Somatic chromosome length ranges from 1.29 m to 3.29 m where as arm ratio ranges from 0.59 to 1.00 m. Karyotypes of these taxa are symmetric. Only metacentric and submetacentric chromosomes are found in the somatic complement. Stomatal frequency is lesser in triploid variety when compared to diploid varieties.
Chromosome number
Morpho
Cite
Citations (3)
1. Detailed karyotype analysis of Zephyranthes mesochloa has been made. In the normal complement, 2n=24 chromosomes have been observed in the present investigation, whereas previous study in the same species has shown 2n=48 chromosomes. The significance of this difference has been discussed. Previous record of chromosome numbers in the genus Zephyranthes has been reviewed. The lowest and the highest number recorded in this genus are 2n=12 and 2n=120 respectively.2. Extensive numerical variation in the somatic chromosome complements has been noticed in Z. mesochloa, including both hypodiploid and hyperdiploid numbers which range from 2n=7+1 fragment to 2n=102. In addition, occurrence of structural chromosomal alterations in the somatic complements has also been noted. The mode of origin of these numerical and structural alterations has been discussed in the light of previous data in the present and other species of this genus as well as other genera of asexually reproducing plants.3. Non-disjunction and endomitotic replication affecting all or several chromosomes of the complement have been suggested as possibly responsible for their origin. The evolutionary importance of such somatic alterations in species reproducing through vegetative means has been pointed out.
Chromosome number
Complement
Cite
Citations (5)