Intrachromosomal Asymmetry Research Articles

Chromosome Analysis of Dendrobium stockelbuschii and Dendrobium sylvanum Orchids

Abstract Dendrobium stockelbuschii and Dendrobium sylvanum orchids are in great demand in Indonesia because of their uniqueness. Plant breeders keep trying to breed this orchid to maintain its uniqueness. Cytological information of D. stockelbuschii and D. sylvanum helps plant breeders in the breeding process. This research aims to determine the cytological characteristics such as chromosome number, size, shape, and karyotype. This study was conducted at the Plant Breeding Laboratory, Faculty of Agriculture, Sebelas Maret University. Data analysis was carried out descriptively based on chromosome observations. The results show that both orchid species have several chromosomes 2n = 38. The average chromosome length in D. stockelbuschii was 1.84 ± 0.52 μm to 2.05 ± 0.54 μm and in D. sylvanum was 2.32 ± 0.64 μm to 2.60 ± 0.68 μm. D. stockelbuschii and D. sylvanum had an average karyotype pattern of 2n = 2x = 38 = 18m + 1sm. The intrachromosomal asymmetry index (A1) value in both species tends to be metacentric, while the interchromosomal asymmetry index (A2) value in all species shows relatively tiny deviations in chromosome size.

Karyological analyses in several Algerian populations of six species of the genus Vicia L. (Fabaceae)

As part of the evaluation and valorization of plant genetic resources of fodder and pastoral interest in Algeria, seventeen (17) natural populations belonging to six (06) species of the genus Vicia (Vicia sativa, Vicia disperma, Vicia monardii, Vicia ohchroleuca, Vicia onobrychioides and Vicia lutea), originated from different ecological regions in the North-Eastern of the country, were considered. The populations have been the subject of mitotic and meiotic studies. Haploid and diploid numbers and chromosome measurements were determined. Original results were observed for the first time in some species. In fact, chromosome counts have revealed some new chromosome numbers. The first number (2n=14, n=7) was observed in the endemic subspecies of Algeria, V. ochroleuca subsp. atlantica and in the species Vicia onobrychioides. The second number (n=6) was observed in the species Vicia disperma. Within Vicia monardii, the three new chromosome numbers, previously observed only in mitosis by our research team, were confirmed for the first time through the present meiosis study (n=6, 7 and 8), indicating that they are A type chromosomes. The base number x=7 is the most frequently observed number in the six Vicia species. The observed chromosome numbers would be related to some ecological factors (altitude, rainfall) of the origin environment of the populations. Chromosome measurements and established karyotypes were determined for the first time in V. monardii, V. onobrychioides and V. ochroleuca subsp. atlantica. Chromosome size and karyotype formula are variable among the studied species and subspecies. Karyotypes vary from symmetrical to asymmetrical and the intrachromosomal asymmetry is higher than interchromosomal one. The new cytogenetic data would contribute to a better understanding of the evolution mechanism of the species in the genus Vicia L.

Karyotype and genome size variation in Delphinium subg. Anthriscifolium (Ranunculaceae).

Five taxa of Delphiniumsubg.Anthriscifolium have been karyologically studied through chromosome counting, chromosomal measurement, and karyotype symmetry. Each taxon that we investigated has a basic chromosome number of x = 8, D.anthriscifoliumvar.savatieri, D.anthriscifoliumvar.majus, D.ecalcaratum, and D.callichromum were diploid with 2n = 16, while D.anthriscifoliumvar.anthriscifolium was tetraploid with 2n = 32. Monoploid chromosome sets of the investigated diploid taxa contained 1 metacentric chromosome, 3 submetacentric chromosomes, and 4 subtelocentric chromosomes. Higher interchromosomal asymmetry (CVCL) was present in D.ecalcaratum and D.callichromum than in other taxa. The highest levels of intrachromosomal asymmetry (MCA) and heterogeneity in centromere position (CVCI) were found in D.anthriscifoliumvar.majus. Diploid and tetraploid genome sizes varied by 3.02-3.92 pg and 6.04-6.60 pg, respectively. Karyotype and genome size of D.anthriscifoliumvar.savatieri, D.anthriscifoliumvar.majus, D.callichromum, and D.ecalcaratum were reported for the first time. Finally, based on cytological and morphological data, the classification of Delphiniumanthriscifolium was revised.

Karyotype ofPhaius tankervilleaeandPhaius amboinensisorchid

Phaius tankervilleaeandPhaius amboinensisorchids are decorative orchids that have high ornamental value and are classified as endangered plants. Genetic information from theP. tankervilleaeandP. amboinensisorchids will be useful for plant breeders to develop a strategy in the ornamental improvement program. The aim of the study was to determine the karyotype pattern ofP. tankervilleaeandP. amboinensisorchids. Chromosomes obtained from meristematic root tips of each species were used to construct a karyotype and idiogram used the squash method. The results showed that the chromosome numbers and karyotype formulae ofP. tankervilleaewas 2n=2x=44=44 m (metacentric) andP. amboinensiswas 2n=2x= 46=44m+2sm (sub-metacentric). Intrachromosomal Asymmetry Index (A1) ofP. tankervillaewas 0,10 andP. amboinensiswas 0,15, indicates that both of them tend to have a metacentric chromosome type. Interchromosomal Asymmetry Index (A2) ofP. tankervillaewas 0,37 andP. amboinensiswas 0,34, indicates that both have sufficient varies in size of chromosomes.

How many species of tulips of the subgenus Orithyia (Tulipa, Liliaceae) are in Southern Siberia?

The subgenus Orithyia in the genus Tulipa is considered one of the least studied. It includes the most eastern species of tulips. Previously, three species of tulips from this subgenus, T. heteropetala, T. uniflora, and T. mongolica were reported for the territory of Southern Siberia. The morphological analysis showed that studied plants, from populations previously reported in Southern Siberia under the name T. heteropetala, are large individuals of T. uniflora. There was a high level of morphological differences between all populations of T. uniflora and T. mongolica. Karyotype analysis showed that T. mongolica, T. uniflora, and T. siniangensis have similar karyotype structures. In T. heterophylla, in comparison with them, a lower level of intrachromosomal asymmetry was noted. Molecular genetic analysis confirms previous data and separates the subgenus Orithyia among other subgenera in the genus Tulipa. Molecular data confirmed taxonomic affiliation of specimens from the Zabaykalsky Territory (Russia) previously assigned by morphological characters to T. mongolica. Thus, it was confirmed that two species of tulips of the subgenus Orithyia, Tulipa uniflora and T. mongolica, grow in the studied area.

KARYOTYPE ANALYSIS OF PACHIRA (PACHIRA AQUATICA)

Pachira aquatica belongs to the Bombacaceae group, the clades in the family Malvaceae. The subfamily contains about 304 species, most with high economic and medicinal values. Considering their importance, some of the plants attained special cultural status. Pachira comes from Central America and South America, introduced and spread to Europe, Africa, and Asia. The diversity of plant morphology can result from environmental factors interacting with genetic features, then expressed as phenotypes. Geographic isolation can prevent gene flow between populations. Geographic separation allows mutations to occur, and natural selection and genetic drift can alter allele frequencies differently in separate populations leading to allopatric speciation. The present study aims to determine the characteristics and chromosomal composition of P. aquatica. This study used the squashing method, often employed to obtain chromosomes by squeezing the preparations. The results showed that the number of chromosomes of pachira was 2n = 66. The chromosome length of pachira ranged from 0.812±0.009 to 1.955±0.009 μm. The chromosome shape of pachira is metacentric. The karyotype arrangement of pachira is 2n = 2× = 29m + 4sm, where 2n equals to 29 pairs of metacentric chromosomes and four pairs of submetacentric chromosomes. The intrachromosomal asymmetry index (A1) of the chromosome of pachira scored at 0.19±0.001, with the value of the interchromosomal asymmetry index (A2) at 0.224±0.021.

Genetic diversity using biochemical, physiological, karyological and molecular markers of Sesamum indicum L.

The genetic diversity and the relationships among sesame cultivars were investigated using physiological and cyto/molecular analysis. To our information, no studies have yet been conducted on the genetic evaluation of sesame genotypes based on cyto/molecular analysis in Saudi Arabia. This study showed that genotype Bah-312 had the highest values from physiological and biochemical traits (plant height, harvest index, total plant dry matter, seed yield, oil content, and fatty acids content). Using 20 ISSR and 25 SCoT primers, the studied genotypes amplified 233 and 275 alleles, while the average polymorphism percentage (P%) was 65.32% (ISSR) and 77.8% (SCoT) across all the studied genotypes, respectively. To assess the markers efficiency analysis the polymorphism information contents (PIC), Marker Index (MI), Effective Multiplex Ratio (EMR), Resolving Power (Rp) were estimated. In general, primers (ISSR 2 & SCoT 21) and (ISSR 4 & SCoT 3) revealed the highest and lowest values for P %, PIC, MI, and EMR%. Furthermore, 188 positive and negative unique bands were detected, out of which ISSR generated 84, while 104 were amplified by SCoT analysis. In this regard, genotype Bah-312 generated 41 unique amplicons, and Jiz-511 genotype 23 unique amplicons. In the same context, the population genetics parameters, number of different alleles (Na), number of effective alleles (Ne), Shannon’s index (I), expected heterozygosity (He), and Unbiased Expected Heterozygosity (uHe), were calculated. ISSR marker showed the highest values for all the estimated parameters. In this regard, genotype Bah-312 exhibited the highest values (1.35, 1.37, 0.31, 0.21, 0.29) & (1.31, 1.35, 0.30, 0.20, 0.27) while, genotype Ahs-670 revealed the least values (1.29, 1.31, 0.26, 0.16, 0.23) &(1.14, 1.26, 0.22, 0.15, 0.20) for ISSR and SCoT markers respectively. For cytological data, according to the highest asymmetry index (AsK%) and lowest total form percentage (TF%) values, genotype Ahs-670 was the most advanced cultivar, and genotype Bah-312 was the most primitive one. According to the degree of asymmetry of karyotype (A) and intrachromosomal asymmetry index (A1), sesame genotype Ahs-670 was the most asymmetrical, and Bah-312 was the most symmetrical genotype. This study gives some helpful information about the genetic diversity of six sesame landraces. The variation harbored by these landraces could be used in sesame breeding programs.

Karyotype and genome size variation in white-flowered Eranthis sect. Shibateranthis (Ranunculaceae).

Comparative karyomorphological analyses of six out of the eight white-flowered species of Eranthissect.Shibateranthis have been carried out. All studied specimens of E.byunsanensis, E.lobulata, E.pinnatifida, and E.stellata had a somatic chromosome number 2n = 16 with basic chromosome number x = 8. On the contrary, E.tanhoensis and E.sibirica had a basic chromosome number x = 7. The specimens of E.tanhoensis were diploid with 2n = 14, while the specimens of E.sibirica were polyploid with 2n = 42. Monoploid chromosome sets of the investigated diploid species had 4–5 metacentric chromosomes and 2–4 submetacentric/subtelocentric/acrocentric chromosomes. The highest level of interchromosomal asymmetry, estimated via CVCL, was found in E.byunsanensis and E.pinnatifida. The highest levels of intrachromosomal asymmetry (MCA) and heterogeneity in centromere position (CVCI) were found in E.lobulata and E.byunsanensis, while E.sibirica had the most symmetric karyotype. A multivariate PCoA analysis of basic karyotype parameters (2n, x, THL, CVCL, MCA, and CVCI) highlighted no overlap among species accessions, which was also confirmed by LDA. The average absolute monoploid DNA content (1Cx) of the 23 investigated samples of six Eranthis species varied from 9.26 ± 0.25 pg in E.sibirica to 15.93 ± 0.32 pg in E.stellata. Overall karyological affinity was highlighted between E.lobulata and E.stellata, on one side, and between E.byunsanensis and E.pinnatifida, on the other side. Interestingly, there was no significant correlation between total haploid (monoploid) chromosome length (THL) and 1Cx values in these species.

CONVENTIONAL AND G-BANDING KARYOTYPE VARIATIONS OF THREE DUCK BREEDS OCCURRING IN EGYPT

In the present work, the chromosome variation and comparative analysis of conventional and G-banding karyotypes between three duck breeds (Pekin, Soudani and Baladi) occurring in Egypt were carried out. Almost all examined cells of the three studied duck breeds showed 7 macro-chromosome pairs and Z, W and 64 microchromosomes (less than 1 micron in size and so called microchromosomes). Some of karyological parameters such as chromosome length, q and p arm lengths, arm ratio, Intra chromosomal asymmetry degree (AsD) and karyotypic asymmetry (AsK) were calculated. Results showed notable differences of the karyotype characteristics between the three studied duck breeds. Likewise,the studies macrochromosomes showed three different categories of karyotypic formulas were obtained (1m+7sm+1st for Baladi, 3m+6sm for Pekin and 9sm for Sudani) including sex chromosomes. Into AsD and AsK parameters also varied among the studied breeds. There was visible variation in the G- banding patterns and their constructed physical maps of the seven pairs of autosomes and sex chromosomes between the three studied duck breeds.

Karyotypical Identification of Some Important Alfalfa (Medicago sativa L.) Lines in Turkey

Chromosome line and characterization of nine Turkish alfalfa (Medicago sativa L.) lines were investigated using karyological techniques in this study. Root tips were obtained from germinated alfalfa seeds in petri dishes at room temperature (25°C) for visualizing somatic chromosomes. The chromosome numbers of nine alfalfa lines were determined as 2n=4x=32. The karyotype formula of 2n=32= 30m+ 2sm (30 median + 2 submedian) were noted for Line 1, 2and 3. Whereas, Line 4, 6, 8, 9 showed the karyotype formula of 2n=32=32m (32 median). The karyotype formula of Line 5 and 7 were 2n=32=28m+4sm (28 median + 4 submedian). Satellite chromosome pairs were observed from Line 5. The results of the karyotype asymmetry index analysis showed that intrachromosomal asymmetry is higher than interchromosomal asymmetry in the karyotypes of alfalfa lines.

Karyotypic analysis of Pigeon pea (Cajanus cajan L.)

Pigeon pea has great potential to be alternate source of plant protein. The potential of pigeon pea needs to be improved by plant breeding program. Genetic information are needed to improved plant breeding. This research aims to gain genetic information based on chromosome numbers, chromosome shape and chromosome length to visualize pigeon pea karyotypic. The research was conducted at Plant Physiology and Biotechnology Laboratory Faculty of Agriculture Sebelas Maret University and Plant Breeding Laboratory Mendel Room Faculty of Agriculture Gadjah Mada University. This research had be done by making glass slides using squashing method include fixation use Carnoy 1 solution (3 absolute ethanol: 1 96% acetic acid), hydrolysis (1N HCl) and chromosome staining (aceto orcein 2%). The results showed that chromosome number of pigeon pea is 2n = 2x = 22 with chromosome length 5.73 ± 1.15 μm until 10.92 ± 2.69 μm. Shape of pigeon pea chromosomes are metacentric and submetacentric which are metacentric is dominant. Karyotypic formula of pigeon pea is 2n = 2x = 9 m + 2 sm. Intrachromosomal asymmetry index (As1%) of pigeon pea is 59% and Intrachromosomal asymmetry index (A2) value of pigeon pea is 0.34 ± 0.02.

Cytogenetic Diversity and Characterization of Vicia sativa Subspecies

Background: Vicia sativa L. is variable genus comprised of several subspecies. Close relative species and subspecies of the cultivated species are easily usable gene sources because they have gained resistance against a wide range of biotic and abiotic stresses. The main objectives of this study are to identify and describe the cytogenetical and karyological characteristics of subspecies in the Vicia sativa complex.Methods: The research material consisted of multiple entries collected from the five subspecies of nine taxa. All cytological observations made from root tips. Six chromosomal parameters (chromosome length, relative length, long arm length, short arm length, arm ratio and centromeric index) and five karyotype asymmetric parameters (difference in relative length, total form percentage, intrachromosomal asymmetry index, interchromosomal asymmetry index and mean centromeric asymmetry) were determined.Result: It was determined that the chromosome number of subspecies were 2n =10-12. The haploid chromosome lengths of subspecies were 15.86-33.88 µm and the average chromosome lengths varied between 2.64-5.65 µm. According to the intrachromosomal karyotype asymmetry index analysis, subsp. segetalis was the most asymmetric karyotype and subsp. sativa “Antalya” was the most symmetric karyotype. According to the interchromosomal karyotype asymmetry index analysis, subsp. angustifolia was the most asymmetric karyotype and subsp. nigra was the most symmetric karyotype.

Chromosome diversity and karyotype asymmetry analysis in four cultivated triploid and three diploid wild genotypes of Musa from North-East India

Ploidy and karyotype asymmetry of four cultivated Musa acuminata var. Luwaobi, var. Masung Tabi, var. Gopi and var. Poitrish Kola (2n = 3x = 33) and three wild seeded M. acuminata var. Ram Kola, Musa balbisiana var. Blung Thali and Musa laterita (2n = 2x = 22) were reported for the first time from North East India. The predominance of median constricted chromosomes was found as compared to sub-median constricted chromosome in all genotypes. The average chromosome length varied from 1.55 μm in var. Luwaobi to 1.92 μm in var. Ram Kola. Symmetric karyotype was recorded in the wild as compared to the cultivated Musa genotypes. Out of the twelve inter- and intra-chromosomal asymmetry indices studied, intra-chromosomal asymmetry index (A1) versus inter-chromosomal asymmetry index (A2), relative variation in the centromeric index (CVCI) versus relative variation in chromosome length (CVCL) and heterogeneity of chromosome length (AI) versus dispersion index were found most reliable to assess chromosome asymmetry. Most symmetric karyotype was found in var. Poitrish Kola of Tripura and most asymmetric karyotype was found in var. Luwaobi of Manipur among cultivated genotypes. Genotype var. Ram Kola showed more karyotype asymmetry among the wild Musa as compared to var. Blung Thali of Tripura and M. laterita of Sikkim. Phylogenetic tree obtained from chromosome characters revealed that var. Ram Kola has ancestral karyotype and was found to be distantly related from the others. Two wild seeded genotypes M. balbisiana var. Blung Thali and M. laterita were found to have close relationship with AB genome suggesting the phylogenetic ancestry with AA or AAA genotypes.

New report on karyotype and idiogram of two Zingiber species, Z. ligulatum and Z. parishii subsp. phuphanense from Thailand

The genus Zingiber of the family Zingiberaceae is a perennial herb that possesses underground tuberous aromatic rhizomes and currently comprises approximately 56 species in Thailand. Somatic chromosome numbers and karyotypes of two species of Zingiber found in the northeast Thailand are presented here. Present study is the first account of the karyotype formula of the examined species which could be depicted as: 2n (22) = 10m + 12sm for Z. ligulatum and 2n (22) = 16m + 6sm for Z. parishii subsp. phuphanense. A detailed account of karyomorphology and estimates of asymmetry index, total form percent, ratio of mean length of short arms to long arms, intrachromosomal asymmetry index, interchromosomal asymmetry index, and centromeric index are also provided suggesting that the two species fit into the 1C category proposed by Stebbins. These results could be useful in cytogenetic studies of Zingiber populations and comparative analysis of the karyotypes and idiograms of Zingiberaceae species found in Thailand.

A study on genetic relationship between Allium sativum L. and Scadoxus multiflorus (Martyn) Raf. of Amaryllidaceae

The present investigation has been focussed on the inter-chromosomal and intra-chromosomal asymmetry data of Allium sativum and Scadoxus multiflorus of Amaryllidaceae using quali-quantitative and quantitative methods. The quail-quantitative analysis is strictly ratio based and it revealed that the karyotype of A. sativum and S. multiflorus belonged to category 1A and 3C respectively indicating only the degree of asymmetry. The coefficient of variation of chromosome length (CVCL) and the mean centromeric asymmetry (MCA) were the estimators of quantitative analysis and the data showed that the inter- and intra-chromosomal asymmetry were comparatively high in S. multiflorus than that of A. sativum. Further, the genetic distance between these two species is clearly visible in the bi-dimensional scattered plot from the derived MCA and CVCL data.

Biosystematic study of the Egyptian Datura stramonium (Solanaceae)

Datura stramonium (Solanaceae) is an annual weed found in most temperate and subtropical regions of the world. The taxonomic identity of this species is still under debate since Linnaeus first published the name. Early on, many varieties and forms were recognized. In Egypt, D. stramonium presents in two forms: the white-flowered ‘stramonium’ form and violet-flowered ‘tatula’ form. Some authors treated D. stramonium and D. tatula as two distinct species, while others included D. tatula within D. stramonium as either a variety or forma. The present study aimed to elucidate the taxonomic identity of both the white ‘stramonium’ and the violet ‘tatula’ forms based on morphological, palynological and cytogenetic studies extended to karyotyping. A taxonomic study of these forms was carried out using 75 morphological and pollen characters. Significant morphological differences were observed; the most important ones were flower and stem colour, in addition to flower and fruit dimensions. The anatomical examination of juvenile-fruit in acropetal transverse sections, revealed the gradual displacement of parietal placentation at the fruit base to axile at the fruit apex. Pollen of both forms showed no significant differences. Cytogenetic results revealed the presence of a diploid chromosome number (2n=2x=24) in both forms, with minor aneuploidy in the ‘tatula’ form. According to the karyotyping, notable differences were found between the two studied forms, including the centromeric index, total genomic length, and intrachromosomal asymmetry index. Morphological and cytogenetic data revealed that the two forms are different enough to be treated taxonomically as two distinct varieties, namely D. stramonium var. stramonium and D. stramonium var. tatula.

Karyological studies of Iranian Allium L. (Amaryllidaceae) species with focus on sect. Acanthoprason. 1. Mitotic chromosomes

Eighteen species and subspecies (34 accessions) of Allium sect. Acanthoprason and 11 species (17 accessions) belonging to other subgenera and sections of Allium were karyologically investigated and include first reports for 12 species. The examined plants of 47 accessions were diploid, three accessions of two species were tetraploid, and in the A. bisotunense accession, we found a mix of di- and triploid individuals. B chromosomes were found in 10 accessions. A basic chromosome number of x = 8 was confirmed for all investigated members of subg. Melanocrommyum and subg. Allium, and x = 9 for Allium tripedale of subg. Nectaroscordum. Idiograms were drawn for each accession, and metaphase images are presented illustrating observed chromosomal variations. Also, karyotype features and asymmetry parameters were calculated for all accessions. Chromosomal aberrations, e.g. aneuploid cells or loss of whole or parts of chromosome arms, were rarely observed. In general, the karyotypes showed low variation in inter- and intrachromosomal asymmetry especially inside of the taxonomic groups, though satellited chromosomes were good markers for subgenera and even specific for two studied sections of subg. Allium. Six different types of satellites were recognized, two of them were newly described: Type P was prevalent in subg. Melanocrommyum, and type O in sect. Codonoprasum. Statistical analyses were performed on five karyological parameters to test correct relationships and also to test previous grouping hypotheses. Although our data confirm distinct karyological characters for the subgenera investigated, the remarkable morphological diversity inside of subg. Melanocrommyum is not mirrored by striking karyological differences.

Karyotypic studies in eight populations of Zhumeria majdae Rech. f. & Wendelbo from Iran

AbstractThe karyotype asymmetry/symmetry of a taxon (eight populations) from different geographic sites of Zhumeria genus is presented. The ploidy level between and within populations was 4x. According to intra-chromosomal asymmetry, population Z2 had the most symmetrical karyotype and population Z7 had the most asymmetrical evolutionary karyotype among the populations. In terms of the Stebbins system, the karyotype of populations can be classified in 1A, 2A and 2B classes. The results of analysis of variance revealed significant differences between the populations based on nine karyotypic traits (p < 0.05 and p < 0.01). Cluster analysis showed that the populations of Zhumeria majdae have been grouped in separate clusters. The results seemed to provide enough genetic evidence to identify different populations and useful data to clarify the interspecific relationships. Detailed karyotype analysis allows us to group the different populations and to postulate relationships among them.

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.

Chromosome count and karyotype of two species of Clematis (Ranunculaceae)

Karyotype morphometric data of two species of the genus Clematis L., a cosmopolitan and diverse genus, were studied. Clematis flammula is a diploid with 2n = 16 chromosomes. It exhibits a gradual decrease in size of chromosomes from 14.83 (±3.6) µm to 7.58 (±3.65) µm. Its karyotype formula (2n = 2x = 16 = 10m + 6sm) differs from those of Clematis orientalis (2n = 4x = 32 = 18m + 8sm + 6st), which is in addition a tetraploid species. The intrachromosomal asymmetry (A1) indicates that C. flammula had the most symmetric karyotype A1 = 0.39 in comparison to C. orientalis (A1 = 0.96). The karyological data available in the literature for the genus have also been discussed against the backdrop of the present analysis. This is the first attempt to present the karyotype morphometric data for the tetraploid cytotype of C. orientalis from India.