scholarly journals Estudios citogenéticos de dos especies y una variedad del género Nyctocereus (Cactaceae)

2017 ◽  
pp. 75
Author(s):  
Guadalupe Palomino-Hasbach ◽  
Socorro Zuleta-Lechuga ◽  
Leia Scheinvar
Keyword(s):  
Chromosome Number ◽  
Central America ◽  
Chromosome Numbers ◽  
Basic Number ◽  
Diploid Chromosome Number

The genus Nyctocereus (Cactaceae) consists of seven species and two varieties distributed from Mexico to Central America. They are valued as ornamental and for its edible fruits. In this study the chromosome numbers were determined and the karyotypes elaborated for N. castellanossi, N. serpentinus and N. serpentinus var. splendens. The diploid chromosome number for the three taxa was 2n = 22 and the karyotypes were very homogenous. No polyploids were detected. The basic number is x= 11. All the chromosomes in N. castellanosii and N. serpentinus were metacentric, while in N. serpentinus var. splendens two pairs of submetacentric chromosomes were observed. The total chromatin length was different for the three species, finding the lowest value in N. serpentinus var. splendens.

The Chromosome Numbers and Nuclear Cytology of Some Common British Serpulids

1960 ◽  
Vol s3-101 (56) ◽  
pp. 395-400
Author(s):  
S. DASGUPTA ◽  
A. P. AUSTIN
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Somatic Cells ◽  
Diploid Chromosome Number ◽  
Iron Alum ◽  
Artificial Fertilization ◽  
Nuclear Cytology

The chromosome numbers of Hydroides norvegica, Mercierella enigmatica, and Pomatoceros triqueter were determined from squashes of somatic cells in young embryos obtained by artificial fertilization, and stained with iron-alum/aceto-carmine. All had a diploid count of zn = 26 chromosomes. Mitotic and meiotic divisions in the 5 species of Spirorbis examined, and in Filograna implexa, all revealed a diploid chromosome number of 2n = 20. A diploid chromosome number of 14 is suggested for the ancestral serpulid.

STUDIES ON SOLIDAGO L.: IV. THE CHROMOSOME NUMBERS OF CERTAIN TAXA OF THE GENUS SOLIDAGO

1959 ◽  
Vol 37 (2) ◽  
pp. 209-228 ◽  
Author(s):  
Jean R. Beaudry ◽  
Denise L. Chabot
Keyword(s):  
North America ◽  
Chromosome Number ◽  
Geographical Distribution ◽  
Chromosome Numbers ◽  
Morphological Characters ◽  
Basic Number ◽  
Western North America

The authors report the chromosome numbers of 25 taxa of the genus Solidago which had not yet been studied from this standpoint, and review the literature. The chromosome numbers of 42 taxa have now been published. The basic number of the genus is nine. Thirty-three taxa are diploid (2n = 18), five are tetraploid (2n = 36), three are aggregate taxa containing both diploid and tetraploid cytodemes, and one is hexaploid (2n = 54). Polyploidy has thus contributed to the evolution of the genus Solidago but it seems that most of the species have differentiated gradually. S. decemflora DC. of western North America differs from S. nemoralis Ait. of the same continent by morphological characters, its geographical distribution, and its chromosome number, the first taxon being tetraploid and the second diploid; the two are thus good species and not only varieties of the same species. The S. rigida of authors is an aggregate made up of two entities which are distinguished not only by their morphology and geographical distribution but also by their chromosome numbers; the eastern one (S. rigida L.) is tetraploid, whereas the western one (S. parvirigida Beaudry) is diploid. The bog and marsh goldenrods, S. Purshii and S. uliginosa, also possess different chromosome numbers, the first being diploid and the second tetraploid.

scholarly journals Peculiarities of chromosomal variability in cultured tissues of Deschampsia antarctica Desv. plants with different chromosome numbers

2016 ◽  
Vol 14 (1) ◽  
pp. 36-43 ◽  
Author(s):  
V. A. Kunakh ◽  
D. O. Navrotska ◽  
M. O. Twardovska ◽  
I. O. Andreev
Keyword(s):  
Tissue Culture ◽  
Chromosome Number ◽  
Chromosome Numbers ◽  
Diploid Chromosome Number ◽  
Deschampsia Antarctica ◽  
Donor Plant ◽  
Modal Class ◽  
Chromosomal Variability ◽  
Diploid Cells

Aim. To clarify the details of chromosome variation in calli derived from D. antarctica plants in the initial passages of the culture in vitro. Methods. Induction of callus from root explants of plants, which were grown from seeds, and consequent subcultivation of tissue culture. Cytogenetic analysis of squashed slides stained by acetic-orcein and counting the number of chromosomes in mitotic metaphase plates. Results. There were analyzed the cultured tissues derived from D. antarctica plants with different chromosome numbers: diploid plants (2n=26), mixoploid plant with B-chromosomes (2n=26+1-3B), and mixoploid plant with near-triploid modal class (2n=36, 38). Analysis of callus tissues of all plants at 2-4 passages revealed mixoploidy, presence of polyploid and aneuploid cells. The modal class in all studied calli was composed of diploid and aneuploid cells with near-diploid chromosome number. The cytogenetic structure of cell population of cultured tissues was found to vary with characteristics of the karyotype of donor plant. The largest range of variation in the number of chromosomes (from 18 to 63 chromosomes) was found in tissue culture of diploid plant (2n=26) from the Galindez Island, and the highest frequencies of polyploid (47 %) and aneuploid cells were in the culture of mixoploid plant with near-triploid modal class from the Big Yalour Island. Conclusions. In different D. antarctica cultured tissues at the early stages of the culture, the modal class was composed of diploid cells and cells with near-diploid chromosome number irrespective of karyotype of donor plant (diploid, mixoploid poliploid).Key words: Deschampsia antarctica Desv., plant tissue culture, chromosomal variability in vitro, mixoploidy.

CYTOTAXONOMIC OBSERVATIONS IN THE GENUS AESCHYNANTHUS(GESNERIACEAE)

2001 ◽  
Vol 58 (1) ◽  
pp. 31-43 ◽  
Author(s):  
M. H. RASHID ◽  
K. JONG ◽  
M. MENDUM
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Seed Morphology ◽  
Basic Number ◽  
Somatic Number ◽  
Basic Numbers

This study is a contribution to the further understanding of cytological patterns in Aeschynanthus(Gesneriacaeae). Chromosome numbers are reported for 12 species from six sections; nine of these are new counts. Two basic numbers, x=16 and x=15, are generally encountered. Aeschynanthus gracilis proved to be of exceptional interest, as its rare somatic number, 2n=28, confirms the occurrence of a third basic number, x=14, in the genus. Variation in chromosome number in relation to seed morphology is examined.

scholarly journals Chromosomal analysis of Astyanax fasciatus (PISCES, CHARACIDAE) from the Araguari river, Uberlândia, MG, Brazil

2006 ◽  
Vol 66 (1a) ◽  
pp. 161-165 ◽  
Author(s):  
A. R. Torres-Mariano ◽  
S. Morelli
Keyword(s):  
Chromosome Number ◽  
Silver Nitrate ◽  
Chromosome Numbers ◽  
Chromosomal Analysis ◽  
Diploid Chromosome Number ◽  
Nucleolar Organizing Regions ◽  
Astyanax Fasciatus ◽  
The Family ◽  
Silver Nitrate Staining ◽  
Parana Basin

The genus Astyanax is one of the most numerous of the family Characidae, comprising a large number of similar-shaped species, but displaying innumerable karyotypic variations in its chromosome number and/or structure. The literature describes A. fasciatus populations with diploid chromosome numbers varying from 2n = 45 to 2n = 48. In this study, A. fasciatus specimens captured in the Araguari River (Alto Paraná basin) were cytogenetically characterized, revealing a diploid chromosome number of 2n = 46. The nucleolar organizing regions (NORs), detected with silver nitrate staining, showed a multiple system with two pairs of marked chromosomes. These findings are congruent with those of other studies involving populations of the same species.

scholarly journals The chromosome constitution of the pomoideæ

1931 ◽  
Vol 108 (758) ◽  
pp. 423-446 ◽  
Keyword(s):  
Chromosome Number ◽  
Chromosome Pairing ◽  
Chromosome Numbers ◽  
Previous Investigation ◽  
Basic Number ◽  
Basic Chromosome Number ◽  
Chromosome Constitution ◽  
Basic Chromosome ◽  
Original Ancestor ◽  
Derived Series

Previous investigation on cultivated varieties of apples have shown that the apparent basic chromosome number is 17, but chromosome pairing, morphology and breeding results indicate that the 34 chromosome form a more complex constitution than that of an ordinary diploid. In a recent paper (Darlington and Moffett, 1930) it was concluded that in the cultivated apples the set of 34 chromosome in the diploid belong to seven types, three of which are represented six times and four them are represented four times. Thus the original ancestor of the apple would have had a basic number of 7, and the present number of 17 is a secondary basic number. The derived series of polyploids with chromosome numbers 34, 51 and 68 are, therefore, secondary polyploids.

CYTOTAXONOMY OF THREE SPECIES OF CENTAUREA ADVENTIVE IN CANADA

1954 ◽  
Vol 32 (1) ◽  
pp. 182-186 ◽  
Author(s):  
R. J. Moore ◽  
C. Frankton
Keyword(s):  
Chromosome Number ◽  
Introduced Species ◽  
Chromosome Numbers ◽  
Diploid Chromosome Number ◽  
Chromosome Counts ◽  
Normal Pollen ◽  
Taxonomic Problem ◽  
First Time

The chromosome numbers of three introduced species of Centaurea are here reported: C. diffusa Lam., 2n = 18; C. maculosa, Lam., 2n = 36; C. repens L., 2n = 26. The chromosome counts of C. diffusa and of C. maculosa, which are here reported for the first time, help to clarify a taxonomic problem. A pappus is usually lacking on the achenes of C. diffusa but is present on those of C. maculosa. As a result, plants of C. diffusa with a short pappus have been considered to be possible hybrids between these species. Three such plants here studied had the diploid chromosome number 18, rather than the triploid number to be expected in such a hybrid. Examination of pollen of suspected hybrid specimens shows that the percentage of normal pollen is high. This fact also supports the belief that plants of C. diffusa with a short pappus on the achene are not hybrids with C. maculosa.

Karyotypic diversification and its contribution to the taxonomy of Eleocharis (Cyperaceae) from Brazil

2010 ◽  
Vol 58 (1) ◽  
pp. 49 ◽  
Author(s):  
Carlos Roberto Maximiano da Silva ◽  
Rafael Trevisan ◽  
Maria Socorro González-Elizondo ◽  
Josué Maldonado Ferreira ◽  
André Luís Laforga Vanzela
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Karyotype Analysis ◽  
Basic Number ◽  
Common Event ◽  
Brazilian Species ◽  
Bivalent Formation ◽  
Chromosome Fission ◽  
Regular Meiosis

A karyotype analysis of 147 populations of 25 Brazilian species of Eleocharis (Cyperaceae) was carried out, including representatives of the three subgenera that occur in the country: Limnochloa, Scirpidium and Eleocharis. The analyses showed chromosomes without centromeres, but with terminal nucleolar constrictions (satellites) in some chromosomes. The chromosome numbers varied from 2n = 6 in E. subarticulata and E. maculosa to 2n = 60 in E. laeviglumis, but the chromosome basic number x = 5 was confirmed. Species of the subgenera Eleocharis and Scirpidium possess fewer and larger chromosomes, while those in the subgenus Limnochloa have small and more numerous chromosomes. These features indicate that the karyotypes of the subgenera Eleocharis and Scirpidium are more closely related, in agreement with morphological and phylogenetical data. The representatives of the section Eleocharis exhibited the largest differences in chromosome number and size, probably due to chromosome fission and fusion. Polyploidy was the most common event in this group. Nevertheless, most of the studied species exhibited regular meiosis with only bivalent formation, even the polyploids, such as in E. geniculata and E. sellowiana. The cytogenetic information obtained showed quite variable karyotypes with chromosomes gradually decreasing in size, and predominance of polyploidy. These results are useful in the differentiation of the subgenera.

scholarly journals Malpighiaceae: correlations between habit, fruit type and basic chromosome number

2003 ◽  
Vol 17 (2) ◽  
pp. 171-178 ◽  
Author(s):  
Ricardo A. Lombello ◽  
Eliana R. Forni-Martins
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Basic Number ◽  
Basic Chromosome Number ◽  
Basic Chromosome ◽  
Monophyletic Origin ◽  
The Family ◽  
Number Variation ◽  
Family Based ◽  
The Relationship

The family Malpighiaceae presents species with different habits, fruit types and cytological characters. Climbers are considered the most derived habit, followed, respectively, by the shrubby and arboreal ones. The present study examines the relationship between basic chromosome numbers and the derivation of climbing habit and fruit types in Malpighiaceae. A comparison of all the chromosome number reports for Malpighiaceae showed a predominance of chromosome numbers based on x=5 or 10 in the genera of sub-family Malpighioideae, mainly represented by climbers with winged fruits, whereas non-climbing species with non-winged fruits, which predominate in sub-family Byrsonimoideae, had counts based on x=6, which is considered the less derived basic number for the family. Based on such data, confirmed by statistic assays, and on the monophyletic origin of this family, we admit the hypothesis that morphological derivation of habit and fruit is correlated with chromosome basic number variation in the family Malpighiaceae.

A new diploid chromosome number for tomato (Lycopersicon esculentum)?

1984 ◽  
Vol 26 (5) ◽  
pp. 636-639 ◽  
Author(s):  
P. Banks
Keyword(s):  
Chromosome Number ◽  
Lycopersicon Esculentum ◽  
Chromosome Numbers ◽  
Centric Fusion ◽  
Diploid Chromosome Number ◽  
Mitotic Chromosomes ◽  
Tomato Chromosome ◽  
Hybrid Variety ◽  
Numerical Variation ◽  
Morphological Differences

The recognized chromosome number of tomato has been 2n = 24. In this paper the chromosome number 2n = 26 is reported in 18 varieties of tomato. One commercial hybrid variety, revealed 25 mitotic chromosomes. This variety, as well as the varieties with 26 chromosomes, appeared to be fully fertile. Different chromosome numbers did not appear to be associated with any morphological differences between the varieties examined. Preliminary meiotic examination of the variety 'Flora-Dade' (2n = 26 mitotic chromosomes) sometimes revealed 12 associations of chromosomes and sometimes 13 associations. Meiotic examination of the variety 'Sunny' (2n = 25 mitotic chromosomes) revealed what appeared to be 12 bivalents. Centric fission may account for the numerical variation of the diploid chromosome number of tomatoes.Key words: Lycopersicon, tomato, chromosome number, centric fusion.

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