Karyotype Asymmetry Index Research Articles

Karyomorphological studies in three species of Argyreia Lour. (Convolvulaceae) from India

In this study, karyotypes of three taxa in the genus Argyreia Lour. were examined. The chromosome counts for A. osyrensis and A. setosa were reported for the first time while somatic chromosome count of A. cuneata was confirmed. The three taxa studied were diploid with 2n = 2x = 30. Highest total chromosome length in Argyreia osyrensis was 54.25 μm with mean chromosome length (MCL) of 3.62 μm. The lowest in Argyreia setosa as 46.04 μm with the mean chromosome length of 3.07 μm. The karyotypes of the species were examined on the grounds of various karyotype asymmetry indices. Two of them, A. cuneata and A. osyrensis fell in the 3A while A. setosa belonged to the 4A category of Stebbins’ classification.

Karyotype Analysis of White, Green and Red Petioles Leaf Beet

Leaf beet is one of the important leaf vegetables which has important ornamental value, and is popular with consumers. Green leaves leaf beet includes three kinds, white petioles, green petioles and red petioles. In this research, we try to obtain cytological parameters on these three leaf beet. The results showed that the relative length of white petioles leaf beet was ranged from 8.47% to 12.98% and max arm ratio was determined 1.53. The karyotype asymmetry index was 55.25%, and the karyotype formula was 2n = 2x = 18 = 18m (2SAT). The relative length of green petioles leaf beet was ranged from 9.95% to 12.44% and max arm ratio was determined 1.77. The karyotype asymmetry index was 57.42%, and the karyotype formula was 2n = 2x = 18 = 16m (2SAT) +2sm. The relative length of red petioles leaf beet was ranged from 9.58% to 12.66% and max arm ratio was determined 1.66. The karyotype asymmetry index was 58.57%, and the karyotype formula was 2n = 2x = 18 = 18m (2SAT). The karyotype characteristics of three kinds of leaf beet were all type 1A. The findings revealed the karyotypic characteristics of leaf beet from the cytogenetic aspects.

药用大黄染色体的核型分析

对药用大黄(Rheum officinale Baill.)的染色体核型进行研究。采用常规根尖压片法分析染色体特征，并利用显微摄影技术对染色体进行分析。结果表明，药用大黄的核型公式为2n = 2x = 22 = 4M + 18m，核型类型为“1A”，核型不对称系数(As.K.%)为54.81%。染色体倍性为二倍体，不存在多倍化现象。药用大黄染色体的数量稳定，形态清晰，可为进一步深入研究奠定基础。 The karyotype of Rheum officinale was analyzed in the present study. The chromosome features were conducted by conventional root-tip squashing method and photomicrography technique. Results were as follows: The karyotype formula of R. officinale from Luanchuan in Henan was 2n = 2x = 22 = 18m + 4M; karyotype was 1A type; karyotype asymmetry index (As.K.%) was 54.81%. Chromosome ploidy was diploid, and no polyploidy was observed. The chromosome number and the morphology of R. officinale are stable and clear, which can provide the foundation for further research.

Cytogenetic characterization of Amaranthus caudatus L. and Amaranthus hybridus subsp. cruentus (L.) Thell.

The present study is aimed to identify genetic variability between two species of Amaranthus viz., A. caudatus and A. hybridus subsp. cruentus, two economically important species, cultivated mainly for grain production. Karyomorphological studies in Amaranthus are scarce, probably due to higher number of small sized chromosomes. Karyomorphological studies were conducted using mitotic squash preparation of young healthy root tips. Karyological parameters and karyotypic formula were established using various software programs and tabulated the karyomorphometric and asymmetry indices viz., Disparity index, Variation coefficient, Total forma percentage, Karyotype asymmetry index, Syi index, Rec index, Interchromosomal and Intrachromosomal asymmetry index and Degree of asymmetry of karyotypes. The mitotic chromosome number observed for A. caudatus was 2n=32 with a gametic number n=16 and A. hybridus subsp. cruentus was 2n=34 with a gametic number n=17. In A. caudatus the chromosome length during somatic metaphase ranged from 0.8698 to 1.7722μm with a total length of 39.1412μm. In A. hybridus subsp. cruentus the length of chromosome ranged from 0.7756 to 1.9421μm with a total length of 44.9922μm. Various karyomorphometry and asymmetry indices analyzed revealed the extend of interspecific variation and their evolutionary status.

Aspidistra ronganensis (Asparagaceae), a new species from limestone areas in Guangxi, China

A new species, Aspidistra ronganensis, discovered in Guangxi Zhuangzu Autonomous Region of southern China, is described and illustrated. It is similar to A. retusa in the shape of the flower, but differs by the perigone tubular (vs. campanulate), 20–25 × 6–8 mm, lobes triangular-lanceolate (vs. deltoid-ovate), apex gradually acuminate (vs. subobtuse), with spurlike basal protuberances (vs. withoutr keels), anthers lineate, ca. 5 × 0. 5–1 mm (vs. ovate, 1.8 ×1.8 mm). The chromosome number of the new species was determined to be 2n = 38 + 1B, and the karyotype was formulated as 2n = 24m + 2sm + 12st + 1B. One B chromosome was observed in the chromosome complement. The average length of chromosome complement is 4.22 μm, the karyotype asymmetry indices CVCL and MCA are 63.24 and 26.20, respectively.

A tool for the analysis of chromosomes: KaryoType

AbstractThe software KaryoType, an improved and completely renewed version of the previously existing NucType, was developed for plant chromosomes. The primary function of the software is to allow efficient chromosome measurements and karyotype analysis from microphotographs. Karyotype characterization usually includes chromosome number, size, arm ratio, centromeric index, relative lengths and karyotype formula. Moreover, KaryoType is also capable of measuring karyotype asymmetry indices such as CVCL, CVCI and MCA, and can recognize chromosome homologues based on chromosome length and arm ratio automatically or manually. This program runs on Windows 7 and above and Mac OS X and is freely available at the website of the University of Sichuan (http://mnh.scu.edu.cn/soft/blog/karyotype/).

Aspidistra revoluta, a new species from limestone areas in Chongqing, China

Aspidistra revoluta (Asparagaceae) is described and illustrated as a new species from limestone areas in southern Chongqing Municipality, China. The new species can be distinguished from the other Aspidistra species by its unique umbrella-like pistil with large revolute stigma lobes that bent downwards and touch the base of the perigone. A detailed morphological comparison among A. revoluta, A. nanchuanensis and A. carnosa is provided. The pollen grains of A. revoluta are subspherical and inaperturate, with verrucous exine. The chromosome number is 2n = 38, and the karyotype is formulated as 2n = 22m + 6sm + 10st. The average length of chromosome complement is 4.50 μm, and the karyotype asymmetry indexes A1 and A2 are respectively 0.37±0.03 and 0.49±0.01.

Karyotype studies on eight populations ofPlantago albicansL. from Algeria

AbstractA karyological study of eight populations of Plantago albicans L. (Plantaginaceae) collected from the central high-plain steppe in the province of Djelfa in Algeria was undertaken for the first time. Chromosome numbers were determined as 2n = 2x = 10 for populations growing at medium altitudes (600–900 m) and 2n = 4x = 20 for those growing at higher altitudes (1000–1300 m) of arid bioclimates. Intermediate chromosome numbers 2n = 6, 8, 9, 12, 14, 15, 17 and 18 were found in individuals of the studied populations and were probably aneuploid forms. The analysis of the karyotype asymmetry indices showed that the diploid cytotype (2n = 2x = 10) is characterized by ancestral chromosomes that are symmetrical, large and homogeneous, while the tetraploid cytotype (2n = 4x = 20) is more evolved with asymmetric, small and heterogeneous chromosomes. Based on our findings, it can be suggested that environmental factors and geographical location might have an effect on the genetic structure and evolution of P....

Karyotype study on 15 populations of Eremostachys laciniata Bunge in Iran

A karyotype study was performed on 15 populations of Eremostachys laciniata Bunge from Iran in order to quantify the extent of cytological variation for use in breeding programmes. Ten mitotic root tip cells at the metaphase stage were prepared from each population by the squash method. The chromosomes of suitable mitotic cells were counted and various parameters, including long and short arm lengths, chromosome lengths, total length of the haploid chromosome complement, arm ratios, and the centromeric index, were measured. All 15 populations were diploid with 2n = 2x = 22 and were differentiated by their karyotypic parameters. All 15 E. laciniata populations occupied Class 1A of Stebbins’ karyotype classification, indicating the presence of a primitive symmetrical karyotype. The size of the mitotic chromosomes was medium, and mean chromosome lengths ranged from 3.84 to 4.77 μm. The shortest chromosome lengths were observed in the Ajabshir population and the longest in the Heydarabad population. The Heydarabad population also had the longest total chromosome length and the Ajabshir population had the shortest total chromosome length. The centromeric indices of the chromosome complements varied from 39.3% to 43.7%. Metacentric chromosomes were the most common in all populations, whereas submetacentric chromosomes were rare. The A1 index varied from 0.215 (Areshtanab) to 0.337 (Til). The A2 index ranged from 0.116 (Til) to 0.143 (Kaleybar), and the karyotype asymmetry index varied between 0.051 and 0.097. The results of a principal component analysis (PCA) showed that the main elements of the first three main principal components accounted for 97% of the total variance. Cluster analysis by Ward’s method indicated that all 15 populations could be classified into three clusters. Finally, the results of the karyotypic parameters showed that the Til, Heydarabad, and Marand populations had higher levels of karyotypic heterogeneity and may be useful when developing breeding programmes.

Karyotype asymmetry in Cynodon Rich. (Poaceae) accessions.

Cynodon is a genus of plants with forage potential that has attracted the interest of breeders. These species have high morphological variability in a large number of varieties and cytotypes, hampering identification. This study aimed to determine the karyotype asymmetry index among accessions of Cynodon to discriminate between them. Karyotype symmetry was based on three estimates, which were compared. The basic number for the genus is x = 9. The results of the chromosome count and DNA quantification, respectively, were as follows: two diploid accessions (2n = 2x = 18 and 1.08 ± 0.094 to 1.17 ± 0.036 pg DNA and ± standard deviation), one triploid accession (2n = 3x = 27 and 1.63 ± 0.017 pg DNA), four tetraploid accessions (2n = 4x = 36 and 1.88 ± 0.069 to 2.10 ± 0.07 pg DNA), and one pentaploid accession (2n = 5x = 45 and 2.55 ± 0.098 pg DNA). C. incompletus var. hirsutus had the longest total length of the haploid lot (29.05 µm), with chromosomes that ranged from 1.7 to 6.2 µm in length. On the basis of the karyotype asymmetry indices, the accessions were divided into two groups: 1) C. dactylon var. dactylon, C. transvaalensis, C. dactylon var. polevansii, three accessions of Cynodon sp, and C. nlemfuensis; and 2) C. incompletus var. hirsutus. This is the first description of tetraploidy in C. transvaalensis. The karyotypic data facilitated a determination of the degree of proximity between the accessions.

Contribution to the cytotaxonomic knowledge of 10 species ofKlaseaCass. (Asteraceae) from Turkey

In the present study, karyotype analyses of 10 taxa belongs to the genus Klasea Cass. (Asteraceae) were conducted. Somatic chromosome numbers are not a distinctive character of classification of Klasea taxa. All of the taxa were counted as 2n = 30 chromosomes, except for Klasea radiata subsp. biebersteiniana (2n = 60). Although all the taxa have a chromosome number of 2n = 30, they could be differentiated by their karyotype formula and quantitative parameters of the karyotype. Karyotype analysis was performed by means of an Image Analysis System and karyotype asymmetry indices were measured. According to these parameters, karyological relationships among studied taxa were inferred.

Karyotype analysis of theCalligonum mongolicumcomplex (Polygonaceae) from Northwest China

This study focused on the karyotype characters, mitotic metaphase chromosomes, monoploid idiograms and karyograms of the Calligonum mongolicum Turcz. (Polygonaceae) complex which includes Calligonum chinense A. Los., Calligonum gobicum A. Los., Calligonum pumilum A. Los., and Calligonum zaidamense A. Los., which were investigated for the first time. Analysis of somatic metaphases showed that the chromosome numbers and the formulae of the taxa were 2n = 2x = 18 = 8m + 10sm and 2n = 3x = 27 = 8m + 8sm + 2st for C. mongolicum in Qingtongxia, Ninxia Erlianhot, Inner Mongolia; 2n = 2x = 18 = 8m + 8sm + 2st for C. mongolicum in Erjina, Inner Mongolia;, 2n = 2x = 18 = 6m + 12sm for C. mongolicum in Yumen, Gansu; 2n = 2x = 18 = 8m + 8sm + 2st for C. chinense in Zhangye, Gansu; 2n = 2x = 18 = 6m + 12sm for C. gobicum in Ejina, Inner Mongolia; 2n = 2x = 18 = 4m + 14sm for C. pumilum in Hami, Xinjiang; and 2n = 2x = 18 = 10m + 8sm for C. zaidamense in Zhangye, Gansu. No satellites were observed in the karyotypes of these taxa. Karyotype asymmetry was estimated by Stebbins classification, karyotype asymmetry index (As.K %), total form per cent (TF %), Rec and Syi indices, intrachromosomal asymmetry index (A1) and interchromosomal asymmetry index (A2), dispersion index (DI), degree of asymmetry of karyotype (A index), asymmetry index (AI), coefficient of variation of centromeric index (CVCI), mean centromeric asymmetry (MCA), and coefficient of variation of chromosome length (CVCL).

Karyotype analysis of the hexaploidAspidistra sutepensisK. Larsen

The karyotype of Aspidistra sutepensis, a rare species endemic to Thailand, is described here as a hexaploid for the first time. In disagreement with a previous report, A. sutepensis in this study, has a chromosome number of 2n = 114 and is karyotypically formulated as 2n = 72m + 6sm + 36st. From the mean values of three individual karyotypes, the average chromosome length is determined as 5.26 μm ± 0.2, and the karyotype asymmetry indices A1 and A2 are respectively 0.37 ± 0.01 and 0.61 ± 0.01.

Cytogenetic studies on some Scorzonera L. s.l. (Asteraceae) taxa from Turkey

In the present study, chromosome morphology of 32 Scorzonera L. Taxa, including 19 species endemic to Turkey, was analyzed. The plant materials were collected from different natural populations of Turkey between 2005 and 2011. The classification of chromosomes, the length of the long and short arm, haploid chromosome length, arm ratio, and relative chromosomal length were measured by software image analyses. The basic chromosome numbers were determined as x = 6 and x = 7. Two types of ploidy levels were observed as diploidy and tetraploidy. Karyotype asymmetry indices, TF%, As K%, Syi, Rec, A, A1, and A2 were also calculated. Scorzonera ahmet-duranii S.Makbul and Coskuncelebi, S. Laciniata subsp. Calcitrapifolia (Vahl) Marie, and Scorzonera suberosa C.Koch subsp. Cariensis (Boiss.) Chamberlain had the most symmetrical karyotypes for the subgenera Scorzonera L., Podospermum (L.) DC., and Pseudopodospermum (Lipsch. And Krasch.) Lipsch., respectively.

Karyotype studies endemic plant speciesAstragalus sericeocanusGontsch.(Fabaceae) around Lake Baikal, Siberia

A study of the karyotype and chromosome of six Astragalus sericeocanus populations from different parts of Lake Baikal’s shoreline was undertaken. Each population had the same chromosome number, 2n = 16. The population was divided into three groups depending on the karyotype formulae 2n = 16=8m+8sm, 2n = 16=6m+10sm and 2n = 16=4m+12sm. The analysis of the karyotype asymmetry indexes showed that population on Millionnyi Island had the most asymmetrical and evolutionary karyotype and the population along the River Turka had the most symmetrical karyotype in all of the populations. The plants from all studied populations have similar chromosome morphology.

New chromosome counts, karyotype analyses and asymmetry indices in some taxa of genus Senecio L. and related genera Tephroseris (Rchb.) Rchb. and Turanecio Hamzaoğlu belong to tribe Senecioneae (Asteraceae) from Turkey

In this study, the somatic chromosome numbers and karyotype analyses were determined for nine taxa that belong to three different genera of Senecioneae tribe. The studied taxa are; Senecio tauricolus V.A.Matthews, Senecio racemosus (M.Bieb.) DC., Senecio paludosus L., Senecio trapezuntinus Boiss., Senecio inops Boiss. & Balansa subsp. inops, Turanecio pandurifolius (K.Koch) Hamzaoglu, Turanecio hypochionaeus (Boiss.) Hamzaoglu, Turanecio eriospermus (DC.) Hamzaoglu, Tephroseris integrifolia (L.) Holub. subsp. aurantiaca (Hoppe ex Willd.) B.Nord. S. tauricolus, S. trapezuntinus, S. inops subsp. inops and T. hypochionaeus taxa are endemic to Turkey. The chromosomal variability in the tribe Senecioneae has observed the existence of four chromosome numbers: 2n = 38, 2n = 40, 2n = 46 and 2n = 80. The chromosome number 2n = 38 is a new record for Turanecio species. All taxa existed karyotypes measured by a set of median to submedian chromosomes and a smaller number of subterminal chromosome pairs. Also their karyotype asymmetry indices (TF %, As K %, Syi, Rec, A, A 1 and A 2) were calculated. The ideograms and detailed chromosome morphology measurements of the species were performed by the use of image analysis system (Bs200Pro). This is the first account of somatic chromosomes and karyotypes for the studied taxa except for S. paludosus. The research has contributed to the taxonomic revision of the tribe, Senecioneae, in Turkey.

Karyomorphometry on three polyploid species of Arum L. (Araceae, Aroideae)

In this study three polyploid Arum Linnaeus, 1753 species from Southern Italy were chromosomally investigated. Arum italicum Miller, 1768 was found to have 2n = 84 chromosomes and a karyotype composed of numerous asymmetric chromosomes. Arum maculatum Linnaeus, 1753 and Arum apulum (Carano) P. C. Boyce, 1993 were found to have 2n = 56 chromosomes. In the examined taxa some chromosome pairs were characterized by the presence of weakly coloured Feulgen-stained segments. The karyotype morphology of Arum italicum was found to be similar to that of Arum maculatum, but the more asymmetrical karyotype and numerous weakly coloured Feulgen-stained segments observed in the former suggest the existence of more extensive rearrangements. In contrast, Arum apulum was observed to have a symmetrical karyotype. The A1, A2 and SYi karyotype asymmetry indices are presented. The relationships between these taxa in terms of karyotype morphology and evolution are discussed.

Karyotype analysis of Rheum palmatum.

Rheum palmatum, one of the source plants of the traditional Chinese medicine rhubarb, is anendemic and endangered species. To our knowledge, this is the first report on the chromosome number and karyotype of this species. Sectioning combined with micrography was used to analyze the karyotype. The following results were obtained: R. palmatum had a stable chromosome number 2n = 22; the basic number of chromosomes was 11; karyotype formula is 2n = 22 = 20 metacentric + 2 submetacentric, belonging to Stebbins' 1A type; and karyotype asymmetry index was 55.39%. The present study showed that R. palmatum has a primitive type of karyotype.

Analysis of karyotype diversity of 40 Chinese chrysanthemum cultivars

AbstractTo investigate the genetic differences in Chinese large‐flowered chrysanthemum (Chrysanthemum×morifolium Ramat.) cultivars, we selected 40 typical and stable cultivars on which to carry out cytological studies using karyotype analysis. The results showed that 67.5% of these cultivars were hexaploid‐based aneuploid and that the proportion of hexaploid decreased with passing time. Moreover, 35% of the cultivars had 1–4 satellite chromosome(s). The probability of satellite chromosomes rose with increasing chromosome number. Most of the karyotypes were 2A and 2B. The probability of types 2A and 2C also increased with increasing ploidy of the cultivars. The mean of long‐/short‐arm ratio and the variation of long‐/short‐arm ratio were positively correlated (r2 = 0.72). There was no obvious difference in the asymmetry coefficient of karyotypes, but the discrepancy in the variance of karyotype asymmetry index and relative length of chromosomes was quite distinct. In terms of karyotype parameters, the petal types of chrysanthemums were classified to five groups as flat, tubular, spoon, abnormal, and anemone. We did not observe any obvious orderliness among flower head types. Considering the relationship between karyotype parameters and phenotypic characters, variation of long‐/short‐arm ratio and asymmetry coefficient of karyotypes had the greatest relevance toward most phenotypic characters. The above results indicate that karyotype parameters possess great values for cultivar identification, classification, and genetic analysis in chrysanthemums.

Karyomorphology of Aspidistra grandiflora H. J. Tillich from Indonesia

The karyotype of Aspidistra grandiflora from Indonesia is described here for the first time. A. grandiflora has a chromosome number of 2n = 38 and is karyotypically formulated as 2n = 17 m + 11sm + 10st. The average chromosome length is 5.07 μm, and the karyotype asymmetry indexes A1 and A2 are respectively 0.44 and 0.60. The cytomorphology of A. grandiflora is remarkably different from those of the cytologically reported species in this genus with heteromorphy in chromosome size and morphology of the IXth pair of chromosome complement.