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.

Variation in chromosome number in the Manuleae (Scrophulariaceae) and its cytotaxonomic implications

1993 ◽  
Vol 50 (3) ◽  
pp. 365-379
Author(s):  
K. Jong
Keyword(s):  
Chromosome Number ◽  
South African ◽  
Chromosome Numbers ◽  
Somatic Number ◽  
Basic Numbers

Chromosome numbers for 11 genera and 36 species in the predominantly South African tribe Manuleae (Scrophulariaceae) are presented, the majority being first reports. The basic numbers of the genera form a dysploid series, x = 6, 7, 8, 9. The somatic number of most of the species is diploid, ranging from 2n = 12 to 2n = 18; that of Jamesbrittenia, 2n = 24, is probably of polyploid derivation. The highest somatic number encountered in this survey is that in Camptoloma lyperiiflorum, with 2n = c.56, which, taken in conjunction with a published count of 2n = 28 for another species of Camptoloma, is octoploid based on x = 7. This is the only example, so far, of intrageneric polyploidy in the Manuleae. The somatic number in certain genera appears to be constant over some subgeneric divisions (e.g. Jamesbrittenia, 2n = 24), but variable in others (e.g. Sutera, 2n = 12, 14). The variation in chromosome number observed in this study parallels and corroborates the redefinition of generic boundaries proposed by O. M. Hilliard. One species of Selago (in the tribe Selagineae) was also included in this survey for cytological comparison with Tetraselago (Manuleae).

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 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.

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.

Chromosome numbers from pollen in some North American Impatiens (Balsaminaceae)

1974 ◽  
Vol 52 (12) ◽  
pp. 2637-2639 ◽  
Author(s):  
C. C. Chinnappa ◽  
L. S. Gill
Keyword(s):  
North America ◽  
Chromosome Number ◽  
North American ◽  
Chromosome Numbers ◽  
Herbarium Specimens ◽  
Chromosome Counts ◽  
Present Survey ◽  
The One ◽  
Basic Numbers

Chromosome counts for eight species of Impatiens from North American populations have been determined from herbarium specimens. The chromosome number n = 10 for I. ecalcarata Blank, is a new report. It is apparent from the present survey that there are at least three basic numbers (n = 7, 10, and 13) represented in North America as opposed to the one (n = 10) suggested by the earlier workers.

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.

scholarly journals Chromosome numbers in Bromeliaceae

2000 ◽  
Vol 23 (1) ◽  
pp. 173-177 ◽  
Author(s):  
Ana Lúcia Pires Cotias-de-Oliveira ◽  
José Geraldo Aquino de Assis ◽  
Moema Cortizo Bellintani ◽  
Jorge Clarêncio Souza Andrade ◽  
Maria Lenise Silva Guedes
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Basic Number ◽  
B Chromosomes ◽  
First Time

The present study reports chromosome numbers of 17 species of Bromeliaceae, belonging to the genera Encholirium, Bromelia, Orthophytum, Hohenbergia, Billbergia, Neoglaziovia, Aechmea, Cryptanthus and Ananas. Most species present 2n = 50, however, Bromelia laciniosa, Orthophytum burle-marxii and O. maracasense are polyploids with 2n = 150, 2n = 100 and 2n = 150, respectively, while for Cryptanthus bahianus, 2n = 34 + 1-4B. B chromosomes were observed in Bromelia plumieri and Hohenbergia aff. utriculosa. The chromosome number of all species was determined for the first time, except for Billbergia chlorosticta and Cryptanthus bahianus. Our data supports the hypothesis of a basic number of x = 25 for the Bromeliaceae family and decreasing aneuploidy in the genus Cryptanthus.

scholarly journals New Contribution to the Knowledge on the Chromosome Numbers of Turkish Cerambycidae (Coleoptera)

2021 ◽  
Vol 69 (2) ◽  
pp. 93-99
Author(s):  
Yavuz Koçak ◽  
Elmas Yağmur
Keyword(s):  
Chromosome Number ◽  
Sex Determination ◽  
Chromosome Numbers ◽  
Chromosome Count ◽  
Chromosomal Number ◽  
The Poor ◽  
Karyological Data ◽  
First Time

Information on the karyotypes of Turkish species of Cerambycidae is scanty. Our study contributes to the knowledge of the karyological data (chromosomal number and mechanism of sex determination) of five Turkish longicorn beetles; karyotypes of four taxa, one endemic, are described for the first time and for the remaining one, Purpuricenus budensis (Götz, 1783), the previously published chromosome count is confirmed. The chromosome number of Purpuricenus desfontainii inhumeralis Pic, 1891 and Purpuricenus budensis (Götz, 1783) (Cerambycinae, Trachyderini) was found to be 2n = 28 (13 + Xyp); Clytus rhamni Germar, 1817 and Plagionotus floralis (Pallas, 1773) (Cerambycinae, Clytini) 2n = 20 (9 + Xyp); and the endemic Dorcadion triste phrygicum Peks, 1993 (Lamiinae, Dorcadionini) 2n = 24 (11 + Xyp). In view of the paucity of data available until now, our study is important for both to improve the poor karyological knowledge of Turkish Cerambycidae and to provide an incentive for other researchers.

scholarly journals Karyotype Analysis of Alnus Mill. (Betulaceae) Species Originating From Northeastern Asia

2010 ◽  
Vol 59 (1-6) ◽  
pp. 219-223 ◽  
Author(s):  
Liu Jun ◽  
Ren Bao-Qing ◽  
Luo Peigao ◽  
Ren Zhenglong
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Karyotype Analysis ◽  
Full Potential ◽  
Northeastern Asia ◽  
Ploidy Levels ◽  
Genetic Makeup ◽  
Fossil Records

Abstract Alnus Mill. (alder) is an ecologically valuable tree genus. It is essential to study its genetic makeup in order to use alder trees to their full potential. Five specimens from four Alnus species (A. mandshurica, A. pendula, A. sibirica, and A. sieboldiana), found in northeastern Asia, were subjected to karyotype analysis. The analysis showed that these tree samples could be divided into three categories based on chromosome numbers or ploidy levels: viz., 2n = (4x) = 28, 2n = (8x) = 56 and 2n = (16x) = 112. The differences in chromosome number and karyotype parameters among Alnus species and even within the same species possibly resulted from natural polyploidization. Comparing the chromosome numbers of Alnus species in China with those in Japan showed that there appear to be only two categories in China, whereas there are up to five categories in Japan. The earliest fossil records of Alnus pollen were also discovered in Japan. We conclude that the center origin of Alnus spp. is Japan rather than China.

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