Karyotype Asymmetry Index Research Articles

Molecular cytogenetic characterization of 9 populations of four species in the genus Polygonatum (Asparagaceae).

To characterize the chromosomes of the four species of Polygonatum Miller, 1754, used in traditional Chinese medicine, P.cyrtonema Hua, 1892, P.kingianum Collett et Hemsley, 1890, P.odoratum (Miller, 1768) Druce, 1906, and P.sibiricum Redouté, 1811, and have an insight into the karyotype variation of the genus Polygonatum, fluorescence in situ hybridization (FISH) with 5S and 45S rDNA oligonucleotide probes was applied to analyze the karyotypes of 9 populations of the four species. Detailed molecular cytogenetic karyotypes of the 9 populations were established for the first time using the dataset of chromosome measurements and FISH signals of 5S and 45S rDNA. Four karyotype asymmetry indices, CVCI, CVCL, MCA and Stebbins' category, were measured to elucidate the asymmetry of the karyotypes and karyological relationships among species. Comparison of their karyotypes revealed distinct variations in the karyotypic parameters and rDNA patterns among and within species. The basic chromosome numbers detected were x = 9, 11 and 13 for P.cyrtonema, x = 15 for P.kingianum, x = 10 and 11 for P.odoratum, and x = 12 for P.sibiricum. The original basic chromosome numbers of the four species were inferred on the basis of the data of this study and previous reports. All the 9 karyotypes were of moderate asymmetry and composed of metacentric, submetacentric and subtelocentric chromosomes or consisted of two of these types of chromosomes. Seven populations have one locus of 5S rDNA and two loci of 45S rDNA, and two populations added one 5S or 45S locus. The karyological relationships among the four species revealed by comparison of rDNA patterns and PCoA based on x, 2n, TCL, CVCI, MCA and CVCL were basically accordant with the phylogenetic relationships revealed by molecular phylogenetic studies. The mechanisms of both intra- and inter-specific dysploidy in Polygonatum were discussed based on the data of this study and literature.

Karyotype analysis and genome size estimation of Sapindus mukorossi Gaertn. an economical important tree species in China

ABSTRACT Sapindus mukorossi Gaertn. is a multi-purpose tree used for landscaping and ecological protection, and in the chemical and wood oil industries in China. However, the karyotype and genome size of S. mukorossi are currently unknown, which has hindered the development of novel cultivars and identification of Sapindus species. In this study, we characterized the karyotype and estimated nuclear DNA content of S. mukorossi from southern China. The S. mukorossi karyotype was characterized by 2n = 2× = 28 = 12sm + 16 m, and the karyology analyses of trees from Fujian, Jiangsu, and Zhejiang Provinces gave an average relative chromosome length of 19.13, 22.01 and 22.45 μm, karyotype asymmetry index of 59.78, 60.60 and 60.03, mean centromere index of 38.27, 39.26 and 39.68, and chromosome types classified as “2B”, “2B”, and “1A”, respectively. Using the known genome size of poplar as a standard species, with internal and external standard methods, the genome size in Fujian, Jiangsu, and Zhejiang Provinces was 414.215 ± 0.96, 444.55 ± 10.12 and 439.67 ± 2.01 Mbp; the average size of about 432 Mbp represents a small genome. This study is the first report about karyotype for S. mukorossi and will facilitate future cytogenetic and omic studies of this species, and could serve as a reference for studies on other species related to this genus.

CYTOLOGICAL CHARACTERIZATION OF TOMATO (SOLANUM LYCOPERSICUM L.) GERMPLASM

Germplasm diversity of any crop plays a significant role in the establishment of a successful breeding programme. In this study, five tomato germplasm, namely Roma Savannah, Tima, UTC, Dan Zaria and Tagino were collected from the Nasarawa State College of Agriculture, Lafia were evaluated for their cytological characterization to determine the germplasm cytological karyotyping parameters. The number of chromosomes in all lines was 2n = 24, except for Tagino, in which the number was 2n = 26, whereas chromosome sizes were small, ranging from 322.09 to 461.17µm. The Roma Savannah cultivar was a symmetrical cultivar (primitive), having the highest total form percentage (TF%) and symmetry index (Syi) values and the minimum karyotype asymmetry index (ASK) value, whereas Dan Zaria was asymmetrical (advanced) which makes it a superior germplasm among the other five evaluated. On the whole, the application of cytological techniques could be considered as a means to provide suitable parameters for studying the evolution of the genetic divergence between the studied tomato lines which can aid in preserving genetic resources in gene banks and improving new cultivars in breeding systems.

Comparative karyotype analysis of eight Cucurbitaceae crops using fluorochrome banding and 45S rDNA-FISH.

To have an insight into the karyotype variation of eight Cucurbitaceae crops including Cucumissativus Linnaeus, 1753, Cucumismelo Linnaeus, 1753, Citrulluslanatus (Thunberg, 1794) Matsumura et Nakai, 1916, Benincasahispida (Thunberg, 1784) Cogniaux, 1881, Momordicacharantia Linnaeus, 1753, Luffacylindrica (Linnaeus, 1753) Roemer, 1846, Lagenariasicerariavar.hispida (Thunberg, 1783) Hara, 1948 and Cucurbitamoschata Duchesne ex Poiret, 1819, well morphologically differentiated mitotic metaphase chromosomes were prepared using the enzymatic maceration and flame-drying method, and the chromosomal distribution of heterochromatin and 18S-5.8S-26S rRNA genes (45S rDNA) was investigated using sequential combined PI and DAPI (CPD) staining and fluorescence in situ hybridization (FISH) with 45S rDNA probe. Detailed karyotypes were established using the dataset of chromosome measurements, fluorochrome bands and rDNA FISH signals. Four karyotype asymmetry indices, CVCI, CVCL, MCA and Stebbins' category, were measured to elucidate the karyological relationships among species. All the species studied had symmetrical karyotypes composed of metacentric and submetacentric or only metacentric chromosomes, but their karyotype structure can be discriminated by the scatter plot of MCA vs. CVCL. The karyological relationships among these species revealed by PCoA based on x, 2n, TCL, MCA, CVCL and CVCI was basically in agreement with the phylogenetic relationships revealed by DNA sequences. CPD staining revealed all 45S rDNA sites in all species, (peri)centromeric GC-rich heterochromatin in C.sativus, C.melo, C.lanatus, M.charantia and L.cylindrica, terminal GC-rich heterochromatin in C.sativus. DAPI counterstaining after FISH revealed pericentromeric DAPI+ heterochromatin in C.moschata. rDNA FISH detected two 45S loci in five species and five 45S loci in three species. Among these 45S loci, most were located at the terminals of chromosome arms, and a few in the proximal regions. In C.sativus, individual chromosomes can be precisely distinguished by the CPD band and 45S rDNA signal patterns, providing an easy method for chromosome identification of cucumber. The genome differentiation among these species was discussed in terms of genome size, heterochromatin, 45S rDNA site, and karyotype asymmetry based on the data of this study and previous reports.

Five Species of Taxus Karyotype Based on Oligo-FISH for 5S rDNA and (AG3T3)3

As a relict plant, Taxus is used in a variety of medicinal ingredients, for instance to treat a variety of cancers. Taxus plants are difficult to distinguish from one another due to their similar morphology; indeed, some species of Taxus cytogenetic data still are unclear. Oligo-FISH can rapidly and efficiently provide insight into the genetic composition and karyotype. This is important for understanding the organization and evolution of chromosomes in Taxus species. We analysed five Taxus species using two oligonucleotide probes. (AG3T3)3 signals were distributed at the chromosome ends and the centromere of five species of Taxus. The 5S rDNA signal was displayed on two chromosomes of five species of Taxus. In addition to Taxus wallichiana var. mairei, 5S rDNA signals were found proximal in the remaining four species, which signals a difference in its location. The karyotype formula of Taxus wallichiana was 2n = 2x = 24m, its karyotype asymmetry index was 55.56%, and its arm ratio was 3.0087. Taxus × media's karyotype formula was 2n = 2x = 24m, its karyotype asymmetry index was 55.09%, and its arm ratio was 3.4198. The karyotype formula of Taxus yunnanensis was 2n = 2x = 24m, its karyotype asymmetry index was 55.56%, and its arm ratio was 2.6402. The karyotype formula of Taxus cuspidate was 2n = 2x = 24m, its karyotype asymmetry index was 54.67%, its arm ratio was 3.0135, and two chromosomes exhibited the 5S rDNA signal. The karyotype formula of T. wallichiana var. mairei was 2n= 2x = 22m + 2sm, its karyotype asymmetry index was 54.33%, and its arm ratio was 2.8716. Our results provide the karyotype analysis and physical genetic map of five species of Taxus, which contributes to providing molecular cytogenetics data for Taxus.

Different chromosome numbers but slight morphological differentiation and genetic admixture among populations of the Pulmonaria hirta complex (Boraginaceae)

AbstractHybridization and introgression have a significant impact on the taxonomically controversial genus Pulmonaria. Within this genus, the P. hirta complex shows puzzling systematic relationships among P. hirta s.str. (2n = [22, 26] 28), P. apennina (2n = 22 [26]), and P. vallarsae (2n = 22), showing range overlaps and mixed phenotypes in southern Europe. We carried out morphometric analyses of basal leaves and flower features along with AFLP characterization of 236 plants belonging to 11 populations within the complex and 1 population of P. officinalis. We also implemented an already available phylogeny with sequences from our target populations and characterized their karyotype. For all the populations within the complex, we found molecular evidence of a hybrid origin involving species belonging to different clades (angustifolia and officinalis clades). However, there is a certain morphological differentiation between some populations (“hirtoid” morph) and others (“vallarsoid” morph), albeit single individuals or entire populations show intermediate features. According to our results, hybridization and/or backcrossing/introgression have occurred, and gene flow is currently taking place among these “taxa”. Following the hybridization event(s), we can elaborate three possible evolutionary scenarios: (1) one hybrid “vallarsoid” (2n = 22) species spread across the Italian peninsula, and from this originated the “hirtoid” morph (2n = 28) through dysploidy; (2) two geographically distinct hybridization events produced both “vallarsoid” and “hirtoid” morphs; (3) one “hirtoid” alloploid hybrid species originated and backcrossed with P. officinalis generating “vallarsoid” plants. Under scenarios 1 and 2, the different morphs met again in central Italy, with massive current gene flow. Under scenario 3, “vallarsoid” plants spread across the Italian peninsula, but further backcrossed with “hirtoid” plants in central Italy, leaving pure lineages of “vallarsoid” plants only in the extreme north and south of their range. This latter scenario is supported by populations with 2n = 22, 26 chromosomes, having karyotype asymmetry indices intermediate between those of 2n = 16 and 2n = 28 cytotypes. Irrespective of the evolutionary dynamics, today, a single lineage showing three cytotypes occurs throughout the Italian peninsula, supporting the circumscription of a single polymorphic species, namely P. hirta.

Diploids and polyploids in the Santolina chamaecyparissus complex (Asteraceae) show different karyotype asymmetry

A traditional karyomorphological approach was carried out in order to investigate the cytotaxonomic relationships among the species of the Santolina chamaecyparissus complex. All the 14 species included in this species complex were analysed for a total of 39 populations. Metaphase plates were obtained by squashing root tips stained with Feulgen technique. Measurable metaphase plates available in literature were also re-analysed. Chromosome number (2n), total haploid (monoploid) length (THL), and karyotype asymmetry indices (CVCL and MCA) were calculated for each of the 14 species. Chromosome data are provided for the first time for S. benthamiana and S. vedranensis, while a new hexaploid cytotype is reported for S. villosa. Five different ploidy levels are detected: diploid, triploid (a single individual of the otherwise diploid S. virens), tetraploid, pentaploid, and hexaploid. Our analyses reveal that polyploids are characterized by a more asymmetric karyotype with respect to diploids. The possible origin of polyploids, and in particular of the cultivated pentaploid S. chamaecyparissus, is briefly discussed.

Orcein and DAPI-stained karyotype analysis of Alocasia macrorrhizos (L.) G. Don

Karyotype analyses are required for the identification, characterization, and genetic improvement of any organism. Alocasia macrorrhizos (L.) G. Don. was investigated cytogenetically to determine the karyotypic features. Complex chromocenter type, of interphase nuclei, and gradient type of prophase chromosomes were found in this study. Alocasia macrorrhizos was found to possesses 2n=28 chromosomes. The total length of the 2n chromosome complement was recorded as 98.83±1.39 μm. The range of chromosomal length was 2.50±0.10-4.70±0.10 μm. A gradual decrease in chromosomal length was observed. The total form (TF%) value was found to be 43.58%, Karyotype symmetry index (Syi %) was 77.00 % and karyotype asymmetry index (AsK %) was 56.66%. The centromeric formula was 18m+4sm+2ac, representing asymmetric karyotype. In DAPI banding, the 1.48% positive banded region indicates the lower amount of AT rich repeats in this material. Therefore, Alocasia macrorrhizos could be authentically characterized through karyotype analysis.
 J. Bangladesh Acad. Sci. 45(1); 27-35: June 2021

Comparative karyomorphological analysis of two varieties of Brassica campestris from Bangladesh

Two varieties of the oilseed plant viz. Brassica campestris var. Tori-7 and Brassica campestris var. BARI Sarisha-9 were karyomorphologically investigated following orcein staining. Presence of “Round Pro-chromosome Type” of interphase nuclei and “Continuous Type” of prophase chromosomes indicating that both Tori-7 and BARI Sarisha-9 were originated from common ancestor. Moreover, both the varieties were found to possess 2n=20 chromosomes with almost similar range of length i.e.; 0.90±0.04-2.51±0.05μm for Tori-7 and 0.99±0.06-2.60±0.06μm for BARI Sharisha-9. The total length of 2n chromosome complement was recorded as 29.61±0.76μm for Tori-7 and 29.75±0.80μm for BARI Sharisha- 9 where a slight gradual decrease of chromosomal length was observed in both cases. Average chromosomal length, range of individual chromosomal length, relative length and centromeric index of both varieties were more or less similar. Karyotype symmetry index and Karyotype asymmetry index indicating the symmetric nature of both varieties. All metacentric chromosomes were found in Tori-7 representing strictly symmetric karyotype. Beside metacentric, 2 sub-metacentric chromosomes were found in BARI Sharisha-9 representing almost symmetric karyotype. Thus the two varieties of Brassica campestris -were plants of primitive nature. However, BARI Sharisha-9 can be considered comparatively advanced than Tori-7 based on different cytogenetical features. Therefore, the compilation of these karyomorphological information will be useful for authentic identification and characterization of the two varieties of Brassica campestris which are very basic and important information for breeding in crop improvement programme.
 Jahangirnagar University J. Biol. Sci. 9(1 & 2): 69-77, 2020 (June & December)

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.

Genetic Diversity Analysis of Tomato (Solanum lycopersicum L.) with Morphological, Cytological, and Molecular Markers under Heat Stress

Tomatoes are usually consumed daily in the human diet. High temperatures reduce the number of tomato yields per year. Heat stress has been considered one of the most prominent causes of alterations in morphological and molecular characteristics in crops that decrease normal growth, production, and yield in diverse plants, including tomatoes (Solanum lycopersicum L.). In this study, we evaluated six tomato lines, namely G1, G2, G3, G4, G5, and G6, at morphological, molecular, and cytological levels under heat stress. The average results of two seasons (2018 and 2019) clarified that the G6, G1, and G2 lines recorded the highest flowering values, as well as some fruit and vegetative growth traits. Furthermore, G6 and G2 had the maximum number of fruits/plant, whereas G2 and G1 produced the highest yield/plant under high temperatures. The number of chromosomes in all lines was 2n = 24, except for G5, in which the number was 2n = 26, whereas chromosome sizes were small, ranging from 323.08 to 464.48 µm. The G1 cultivar was a symmetrical cultivar (primitive), having the highest total form percentage (TF%) and symmetry index (Syi) values and the minimum karyotype asymmetry index (ASK) value, whereas G4 was asymmetrical (advanced). Molecular marker analysis demonstrated that intersimple sequence repeat (ISSR) primers 49A, HB-14, 49A, 49B, and 89B presented the highest values for polymorphism percentage P%, marker index (MI), effective multiplex ratio (EMR), and polymorphism information content (PIC), respectively. In contrast, OP-A3, OP-B3, SCoT 2, and SCoT 12 primers showed the highest PIC, EMR, MI, P%, and resolving power (Rp) values across the studied random amplified polymorphic DNA (RAPD) and start codon-targeted (SCoT) primers. Moreover, ISSR revealed the highest number of unique specific markers (6), followed by RAPD (4) and SCoT (3) markers. Cluster analysis of combined cytological data and data relating to molecular marker attributes separated the G1, G2, and G3 lines into one group, whereas the other lines were clustered in another group. On the whole, the application of combined analysis using morphological, cytological, and molecular genetics techniques could be considered to provide suitable parameters for studying the evolution of the genetic divergence between the studied tomato lines.

COMPARATIVE KARYOMORPHOLOGICAL STUDIES OF TWO SPECIES OF CRINUM

Crinum asiaticum L. and Crinum latifolium L. are members of the family Amaryllidaceae. Karyomorphological studies of these two species had been performed by using different quantitative and qualitative parameters to know the karyotype asymmetry, which defines the advanced and primitive nature of these two species. The study revealed that Crinum asiaticum L. and Crinum latifolium L. are diploid with 2n=22 chromosomes. based on Total Chromatin Length, Arm Ratio, Gradient Index, Form Percentage, Total Form Percentage, Karyotype Asymmetry Index, Symmetry Index, and Stebbins classification, Crinum asiaticum L. is more advanced than Crinum latifolium L.

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.

Chromosomal Karyotype Differences of the Dark-Purple Tea Cultivar ‘Ziyan’ and Its Natural Hybrid Progenies

‘Ziyan’ is a new variety of dark purple tender shoots tea tree which is rich in anthocyanins. ZY-1 and ZY-3 were two natural hybridized offspring of ‘Ziyan’, which were cultivated by single plant selection. ‘Ziyan’ is as the female parent, whereas the male parent has yet to be determined. In this study, we try to investigate cytological parameters of the three kinds of tea plants, and analyze the chromosomal karyotype differences among them. The results showed that the max arm ratio of ‘Ziyan’ was determined 2.50, and relative length was between 3.56% and 5.39%. The karyotype asymmetry index was 59.920%, and the karyotype formula was 2n=2x=30=22m (2SAT)+8sm. The max arm ratio of ZY-1 was 2.50, and relative length was between 4.80% and 8.69%. The karyotype asymmetry index was 60.307%, and the karyotype formula was 2n=2x=30=20m+10sm. The max arm ratio of ZY-3 was 2.77, and relative length was between 3.95% and 8.70%. The karyotype asymmetry index was 58.679%, which was lower than ‘Ziyan’ and ZY-3, and the karyotype formula was 2n=2x=30=24m+6sm. Although ‘Ziyan’ was significantly different from its two offspring, the karyotype characteristics of three varieties of tea plants were all type 2B. ‘Ziyan’ had a pair of satellites, but neither ZY-1 nor ZY-3 had a satellite. According to the karyotype asymmetry index and average arm ratio, the hybrid progeny ZY-3 was the most primitive, followed by the female parent ‘Ziyan’, while the hybrid progeny ZY-1 was the most evolutive.

Comparative Analysis of Chromosome Karyotype of Three Varieties of the Characteristic Tea plants

ZY, HYZ and CH-1 are three characteristic tea varieties with different shoot colors. However, there is a lack of karyotype analysis of these characteristic tea varieties. In this experiment, the differences of cytological parameters of three characteristic tea varieties, and the control variety FDDB, were analyzed. The results showed that significant differences of the average arm ratio, relative length, karyotype asymmetry index and the karyotype formula were found among the three characteristic tea varieties as well as the control variety FDDB. Moreover, only ZY’s karyotype type was 2B, while the three other varieties all were 2C. Among them, HYZ was the most evolved and closed to FDDB, while CH-1 and ZY were very different from FDDB and evolved more primitive than HYZ. HYZ was the most evolved, and ZY was relatively primitive. PCA analysis indicated that the notable differences were found between FDDB and two characteristic tea varieties (ZY and CH-1), while HYZ is relatively close to FDDB. This findings revealed the variation of chromosomes among different color varieties at the cytological level, and provided a certain theoretical basis for the study of genetic variation and diversity of tea resources.

Cytotaxonomic investigation and meiotic behavior of natural populations of genus Avena in Algeria

Karyotype and meiotic analysis were performed on forty-five natural populations of genus Avena sampled in contrasting bioclimatic areas of Northern Africa. The diploids (2n = 2x = 14) A. clauda, A. eriantha and A. hirtula are sporadic in hills and mountains of the Tellian Atlas only. A. wiestii (2x) are scattered in arid and semi-arid regions, of which an unexpected 4x population has been discovered. A. barbata (4x) and A. sterilis (6x) are widespread in all bioclimates while A. fatua (6x) is rather rare. Most populations show remarkable novelties in the intra and inter karyotype asymmetry indexes, particularly the 4x cytotype of the endemic A. macrostachya which has almost exclusively metacentric chromosomes. Both 2x, 4x and 6x annual species display regular meiosis with generally bivalent association. Univalents, multivalents, laggards, bridges, asynchronous divisions and micronuclei were often observed. Meiotic behavior observed for the first time in the locus classicus of A. macrostachya, indicate constant occurrence of one or two tetravalents. Meiotic features together with the main bioclimatic parameters, were submitted to a principal component analysis. Significant correlations were found particularly between frequencies of multivalents and laggards with the Mediterranean bioclimatic coefficient and the maximum temperature of the hottest month. These new cytogenetic data have been discussed in the context of the geographical distribution of diploids and polyploids and the aftermath of the local environmental stress conditions on the meiotic process within natural populations.

Karyological investigation of Calotropis gigantea (L.) W. T. Aiton and Centella asiatica (L.) Urban: Two important medicinal plants of Bangladesh

Calotropis gigantea (L.) W. T. Aiton and Centella asiatica (L.) Urban have been medicinally used throughout Bangladesh. In this study, karyotypic features of these two species were studied with orcein staining and banding with two base specific fluorochromes such as chromomycine A3 (CMA) and 4´, 6 diamidino-2-phenylindole (DAPI) for authentic cytogenetical characterization. 2n = 22 and 2n = 18 somatic chromosomes were found in C. gigantea and C. asiatica, respectively. The total chromosome length of C. gigantea and C. asiatica were 45.35 ± 2.64 μm and 63.63 ± 3.19 μm, respectively. The total form percent (TF%), karyotype asymmetry index (AsK%) and karyotype symmetry index (Syi index) were 47.61, 52.39 and 90.87 in C. gigantea and 39.58, 60.42 and 65.51 in C. asiatica, respectively. Both species were found to possess 1A karyotype. In C. gigantea, 2 CMA- and 4 DAPI-bands were observed whereas C. asiatica had 16 CMA- and 6 DAPI-bands. Therefore, the compiled data generated from chromosome analysis on orcein, CMA- and DAPI-banding will be useful for cytogenetical characterization of these two species.

Cytotaxonomy of four Floral Variants of Impatiens Balsamina L.

Karyomorphological characters were investigated in four floral variants of Impatiens balsamina L. viz. white, pink, violet and red for proper characterization and inferring relationships among them. All four floral variants of I. balsamina were found to possess 2n = 14 chromosomes, and ‘Simple Chromocenter Type’ of interphase nuclei was observed in all variants with many small heterochromatin blocks after orcein staining. ‘Continuous Type’ of prophase chromosomes was found in red variant, whereas both ‘Continuous and Gradient Type’ were found in other three variants. The red variant could easily be distinguished from the remaining three variants by total chromosome length, centromeric formula, average chromosome length, total form value, and karyotype asymmetry plus symmetry index. Based on karyomorphology, the white, pink and violet variants of I. balsamina were found very closely related and constituted with similar genome, whereas red variant was found to possess slightly modified genome and distinct from other three floral variants.
 Journal of Bangladesh Academy of Sciences, Vol. 43, No. 1, 1-9, 2019

Karyotype Analysis of Three Varieties of Red Leaf Beet

Red leaf beet was one of the most important leaf vegetables and an ornamental with rich pigment. However, there is a lack of information on genetic variability. In this study, cytological parameters on three varieties of red leaf beet were obtained. The results displayed that the average arm ratio of RR1 was determined 1.52 and relative length was ranged from 9.26% to 13.10%. The karyotype asymmetry index was 59.93%, and the karyotype formula was 2n=2x=18=14m+4sm (2SAT). The average arm ratio of RR2 was determined 1.50 and relative length was ranged from 8.57% to 13.11%. The karyotype asymmetry index was mensurated as 59.60%, and the karyotype formula was 2n=2x=18=14m (2SAT) +4sm. The average arm ratio of RR3 was determined 1.33 and relative length was ranged from 9.44% to 12.56%. The karyotype asymmetry index was 56.85%, which was much lower than RR1 and RR2, and the karyotype formula was 2n=2x=18=18m (2SAT). Although RR3 had an obvious difference with RR1 and RR2, the karyotype characteristics of three varieties of red leaf beet were all type 1A. This research revealed the karyotypic characteristics of red leaf beet. The results indicated that there was an obvious difference among the three varieties of red leaf beet in karyotypic characteristics, and the evolution of red leaf beet was relatively primitive.

Morphological, anatomical and cytological investigations on three taxa of Centaurea L. (Asteraceae) from Turkey

Morphological, anatomical and cytological features of three Turkish taxa of Centaurea L., viz. C. polypodiifolia Boiss. var. polypodiifolia, C. urvillei DC. subsp. urvillei and C. urvillei subsp. armata Wagenitz were investigated. Stem anatomy revealed the presence of a thick cuticle layer outside the stem, and epidermis with dense hairs was observed in the lower part. Investigation on leaf anatomy showed that different types of hairs on the outside of the leaf were very intense. Palisade parenchyma was observed below the upper and lower epidermis. In Centaurea polypodiifolia var. polypodiifolia, chromosome number was found to be 2n=16, while in C. urvillei subsp. urvillei and C. urvillei subsp. armata 2n=20. Total karyotype length of C. polypodiifolia var. polypodiifolia, C. urvillei subsp. urvillei and C. urvillei subsp. armata was 22.9 µm, 37.84 µm and 40.01 µm, respectively. Among the investigated taxa the karyotype asymmetry index was found lowest in C. urvillei subsp. armata. Satellite was detected in C. urvillei subsp. urvillei and subsp. armata, while it was absent in C. polypodiifolia Boiss. var. polypodiifolia.