scholarly journals Estudios cromosómicos en seis especies mexicanas de comelináceas

2017 ◽  
pp. 77
Author(s):  
Guadalupe Palomino-Hasbach ◽  
Balbina Vázquez-Benítez ◽  
Patricia Martínez-Almeraya ◽  
Pedro Mercado-Ruaro

In the present study, chromosome numbers (2n) and karyotypes for the following taxa were obtained: Tradescantia crassifolia Cav. subsp. acaulis (Martens y Galeotti) D. Hunt, Gibasis shiedeana (Kunth) D. Hunt, Cymbispatha commelinoides (Shult. f.) Pichon, Commelina communis L., C. diffusa Burm. f. and C. coelestis Willd. For T. crassifolia subsp. acaulis, this is the first report on chromosome number and karyotype. The species studied were collected in the Reserva Ecológica del Pedregal de San Ángel, México, D.F. The differences encountered in chromosome numbers and karyotypes are discussed. Our results provide evidence that Robertsonian fusions and fisions, structural rearrangements, polyploidy and aneuploidy have an important role in the speciation of Commelinaceae members.

1988 ◽  
Vol 66 (4) ◽  
pp. 672-676 ◽  
Author(s):  
A. E. Stahevitch ◽  
W. A. Wojtas

Chromosome number determinations are reported for 58 accessions, comprising 13 native and introduced taxa of Artemisia found in Canada and the United States. Chromosome numbers observed were n = 8, 9, 18, and 27. A chromosome number of 2n = 18 is the first report for A. pacifica Nutt. A new tetraploid cytotype (2n = 36) was found in A. frigida Willd. Supernumerary chromosomes (n = 9 + 3) and mixoploidy (n = 18, 36) were also observed in this taxon for the first time. Heteroploidy was present in several species. In some taxa, morphological or ecological differences between the chromosomal races were detected; in other cases no differences were noted. Karylogical and phylogenetic evidence is presented for the original chromosome number in Artemisia having been x = 9.


1981 ◽  
Vol 59 (7) ◽  
pp. 1167-1173 ◽  
Author(s):  
J. C. Semple ◽  
R. A. Brammall ◽  
J. Chmielewski

Chromosome number determinations were made from 227 populations of 43 taxa of Euthamia and Solidago. Nearly all were confirmations of previous reports. The majority of the populations sampled were from Ontario. First report: Solidago hispida Muhl. var. tonsa Fern., 2n = 18.


2021 ◽  
Vol 69 (2) ◽  
pp. 93-99
Author(s):  
Yavuz Koçak ◽  
Elmas Yağmur

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.


2010 ◽  
Vol 59 (1-6) ◽  
pp. 219-223 ◽  
Author(s):  
Liu Jun ◽  
Ren Bao-Qing ◽  
Luo Peigao ◽  
Ren Zhenglong

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.


1960 ◽  
Vol s3-101 (56) ◽  
pp. 395-400
Author(s):  
S. DASGUPTA ◽  
A. P. AUSTIN

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.


Bothalia ◽  
1989 ◽  
Vol 19 (1) ◽  
pp. 125-132 ◽  
Author(s):  
J. J. Spies ◽  
E. J. L. Saayman ◽  
S. P. Voges ◽  
G. Davidse

Cytogenetic studies of 53 specimens of 14 species of the genus  Ehrharta Thunb. confirmed a basic chromosome number of 12 for the genus. Chromosome numbers for 13 species are described for the first time. The highest ploidy level yet observed in the genus (2n = lOx = 120) is reported for E. villosa var.  villosa. B chromosomes were observed in several specimens of four different species.


1974 ◽  
Vol 52 (9) ◽  
pp. 2055-2060 ◽  
Author(s):  
L. W. Stephenson ◽  
D. C. Erwin ◽  
J. V. Leary

Nuclear divisions in the hyphae and gametangia of Phytophthora capsici and in hyphae of Phytophthora megasperma var. sojae resembled those of typical mitosis. The chromosomal configurations in prophase are similar to classical angiosperm prophase configurations. However, in metaphase the linear alignment of chromosomes resembled the pattern reported in pollen tubes of Lilium and Tradescantia. The relative size of nuclei and numbers of chromosomes per nucleus remained constant during gametangial development. Somatic and gametangial nuclei were about equal in size and chromosome number. Chromosome numbers in somatic and gametangial nuclei of P. capsici and P. megasperma var. sojae were about six and eight, respectively. There was no evidence of reduction division in gametangia.


1971 ◽  
Vol 13 (4) ◽  
pp. 842-863 ◽  
Author(s):  
S. Ichikawa ◽  
A. H. Sparrow ◽  
C. Frankton ◽  
Anne F. Nauman ◽  
E. B. Smith ◽  
...  

Ninety-one acquisitions of the genus Rumex obtained from various sources were examined taxonomically and cytologically. These acquisitions included 36 species plus 2 unidentified species. The chromosome numbers counted were 2n = 14 (or 15), 16, 18, 20, 40, 42, 60, 80, 100, 120, 140, 160, ca. 170, 180 and ca. 200. The count of 2n = 180 made on one of the R. orbiculatus acquisitions is a new count for this genus, but other acquisitions had 160 and ca. 170. First counts were obtained for four species, R. frutescens (2n = 160), R. crystallinus (2n = 60), R. cristatus (2n = 80) and R. tenax (2n = 80). The count of 2n = 160 for R. frutescens is the highest chromosome number ever reported in the section Axillares. The chromosome numbers determined in R. palustris (2n = 60), R. confertus (2n = 100), R. arcticus (2n = 120) and R. aquaticus (2n = 140) differ from previously published counts. Our counts for eight other species support one of the previous counts where two or more counts are reported. It is shown that the species of the subgenus Acetosa sections Acetosa and Vesicarii and of the subgenus Platypodium have relatively large chromosomes, those of the subgenus Acetosa section Scutati and of the subgenus Acetosella have medium-sized chromosomes, and the members of the subgenus Rumex sections Axillares and Rumex have smaller chromosomes. The chromosomes of the diploid species of the section Rumex were larger than those of the polyploids (4x to 20x) of the same section. Within the section Rumex the log of nuclear volume increased with increasing ploidy, with an abrupt change (decrease) in slope between the 12x and 14x levels.


1984 ◽  
Vol 62 (4) ◽  
pp. 671-673 ◽  
Author(s):  
Douglas E. Soltis

In an attempt to clarify subtribal relationships in tribe Saxifrageae, chromosome numbers and karyotypes were determined for the two species comprising subtribe Leptarrheninae: Leptarrhena pyrolifolia and Tanakaea radicans. In both species 2n = 14, a common chromosome number throughout Saxifrageae. The two species have distinctive karyotypes that appear to differ in the centromeric positions of three pairs of chromosomes. These findings, in conjunction with earlier studies, demonstrate that genera of Saxifrageae often differ karyotypically. Leptarrhena exhibits considerable karyotypic similarity to genera of subtribe Saxifraginae characterized by a base chromosome number of x = 7. Chromosomal data, therefore, do not clearly differentiate subtribes Saxifraginae and Leptarrheninae. This observation is in agreement with evidence from paly-nology and flavonoid chemistry. Karyotypic studies continue to demonstrate the conservative nature of chromosomal evolution in tribe Saxifrageae.


1970 ◽  
Vol 40 (1) ◽  
pp. 53-56 ◽  
Author(s):  
Syeda Sharmeen Sultana ◽  
Hosne Ara ◽  
Sheikh Shamimul Alam

Alocasia fallax Schott and A. odora (Roxb.) Koch (Araceae) were investigated cytogenetically to confirm their taxonomic status. There is no report of 2n chromosome number for A. fallax in the available literature and internet information. Therefore the 2n chromosome number (2n = 28) found in this study is probably the first report for A. fallax. Alocasia odora showed exactly double 2n chromosome number (2n = 56) from A. fallax. In addition to chromosome number, the other karyotypic features of A. odora were exactly double for that of A. fallax. The centromeric formulae of A. fallax was 24 m + 4 sm whereas it is just double in A. odora. Total length of 2n chromosome complement of A. odora (62.58 μm) was almost double to A. fallax. The range of chromosomal length of the two species was almost same. Moreover, A. odora plant is much taller than A. fallax. All of these data suggests that A. odora might be an autotetraploid of A. fallax which in course of evolution had undergone some changes in GC-rich repeats. Key words: Alocasia; CMA; Karyotype analysis DOI: http://dx.doi.org/10.3329/bjb.v40i1.7998 Bangladesh J. Bot. 40(1): 53-56, 2011 (June)


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