THE CYTOLOGY OF EUDESME VIRESCENS (CARM.) J. AG.: I. MEIOSIS AND CHROMOSOME NUMBER

1967 ◽  
Vol 45 (5) ◽  
pp. 665-673 ◽  
Author(s):  
Kathleen Cole
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Reduction Division ◽  
Maximum Diameter ◽  
Cytological Investigation ◽  
Normal Pattern ◽  
Stages Of Development ◽  
Unilocular Sporangium ◽  
Mother Cells ◽  
Complete Process

A cytological investigation of meiosis and chromosome number in Eudesme virescens was conducted on sporophytic field material and cultured gametophytes, using a modified iron acetocarmine squash technique. Meiosis was readily observed in the unilocular sporangium mother cells of the adult sporophyte, sporangia in all stages of development occurring on one thallus at one time. Although the nuclei reach a maximum diameter of only 7 μ, the chromosomes absorb the stain readily and can be distinguished throughout the complete process of reduction division. After meiosis, synchronous mitotic divisions ultimately produce 512 nuclei within the sporangium. At maturity the cone-like depression in the apex of the sporangium everts, and biflagellate zoospores are released. Mitosis in the gametophytes appears to follow a normal pattern. Chromosome numbers of 2n = 20 and n = 10 were recorded.

Cytology of somatic and gametangial nuclei in Phytophthora capsici and Phytophthora megasperma var. sojae

1974 ◽  
Vol 52 (9) ◽  
pp. 2055-2060 ◽  
Author(s):  
L. W. Stephenson ◽  
D. C. Erwin ◽  
J. V. Leary
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Phytophthora Capsici ◽  
Relative Size ◽  
Pollen Tubes ◽  
Reduction Division ◽  
Phytophthora Megasperma ◽  
Linear Alignment ◽  
Size Of Nuclei

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.

scholarly journals Cytological Investigation of Brazilian Nightshade (Solanum seaforthianam Andr.)

2014 ◽  
Vol 15 ◽  
pp. 44-48
Author(s):  
D. Jagatheeswari
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Chromosome Complement ◽  
Basic Chromosome Number ◽  
Cytological Investigation ◽  
Ancestral Species ◽  
Basic Chromosome ◽  
Centromere Position ◽  
Solanaceae Family

Solanum genus namely Solanum seaforthianum Andr. belongs to the Solanaceae family, and comprises only dioeciously species. These plants are distributed between 29º and 40º south. All species of this genus are diploid with chromosome numbers of 2n = 24, 28 and 30. According to literature, the basic chromosome number in this genus is x = 12, 14 and 15. Solanum genus with a chromosome complement of 2n = 30 has a symmetric karyotype with a median and sub median centromere position. Because ancestral species have a symmetric karyotype, it seems that x = 12 is the initial basic chromosome number in this genus and the x = 14 and x = 15 derived from x = 12. So it seems that diploid phenomena played an important role in evolution and speciation

Incomplete bivalent pairing in dihaploids of Brassica napus L

Genome ◽  
1988 ◽  
Vol 30 (3) ◽  
pp. 450-457 ◽  
Author(s):  
William Tai ◽  
H. Ikonen
Keyword(s):  
Brassica Napus ◽  
Chromosome Number ◽  
Anther Culture ◽  
Chromosome Numbers ◽  
Meiotic Behaviour ◽  
Homoeologous Pairing ◽  
Brassica Napus L ◽  
Normal Behaviour ◽  
Mother Cells ◽  
Homoeologous Chromosomes

Twenty five polyhaploid plants (2n = 2x = 19, genome formula AC) of Brassica napus (2n = 4x = 38, AACC) were cytogenetically studied. Seven of these were found among field populations and the rest were derived through anther culture of B. napus cv. Regent. Meiotic behaviour at diakinesis and metaphase I revealed nine bivalents and one univalent in more than 40% of the more than 400 pollen mother cells analyzed. However, when the chromosome number of the polyhaploids was doubled using colchicine, 19 bivalents were observed. These doubled plants (2n = 4x = 38, AACC) also had normal behaviour identical to a regular B. napus at other meiotic stages. Quadrivalent associations were observed when the chromosome numbers were doubled to the octaploid level (2n = 8x = 72, AAAACCCC). It is suggested that A and C are homoeologous genomes. If homologous partners are present, chromosomes would pair within the same genome to form bivalents as occurred in the allotetraploids and to form quadrivalents as occurred in the allooctaploids. However, when a homologous partner is not available, the homoeologous chromosomes would then pair to form bivalents in those polyhaploids.Key words: Brassica napus, polyhaploids, genome relationship, meiotic behaviour, homoeologous pairing.

TETRAPLOID TARAXACUM KOK-SAGHYZ: I. CHARACTERS OF THE LEAVES AND INFLORESCENCES IN THE PARENTAL COLCHICINE-INDUCED GENERATION

1945 ◽  
Vol 23c (4) ◽  
pp. 131-143 ◽  
Author(s):  
M. W. Bannan
Keyword(s):  
Guard Cells ◽  
Stages Of Development ◽  
Pollen Mother Cells ◽  
Mother Cells

Seedlings at different stages of development were treated with colchicine. Successive selections on the aspect of the seedlings soon after treatment, on size of the guard cells at the time of repotting, and finally, after overwintering, on counts of the chromosomes in the pollen mother cells yielded a few hundred plants with tetraploid crowns. These plants bore fewer, broader leaves and fewer, bigger inflorescences with larger achenes than did selected large-celled diploids given the same treatment, but in general the plants were no bigger. A few of the tetraploids were self-fertile (if not apomictic) early in the spring, but later all tested plants proved self-sterile.

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.

Microsporogenesis in Larix laricina

1982 ◽  
Vol 60 (6) ◽  
pp. 797-805 ◽  
Author(s):  
J. Peter Hall
Keyword(s):  
Propionic Acid ◽  
Seed Yield ◽  
Pollen Development ◽  
Abnormal Chromosome ◽  
Acid Mixture ◽  
Larix Laricina ◽  
Normal Pattern ◽  
Mother Cells ◽  
Male Strobili

Microsporogenesis was studied in Larix laricina in eastern Newfoundland at weekly intervals from October to April in four successive seasons. Male strobili were fixed in a 3:1 ethanol – propionic acid mixture, stained in alcoholic carmine, and squashed in 45% acetic acid.Pollen mother cells began development from interphase in early October and passed through leptotene, zygotene, and pachytene by mid-November. They remained in diplotene until mid-March to early April when meiosis was completed over a 2-to 4-week period. Microspores were produced by early May. The pattern of meiotic divisions, their duration, and variability within and between trees in L. laricina was similar to those reported for L. decidua, L. kaempferi, L. sibirica, and L. eurolepis.Deviation from the normal pattern occurred infrequently. In six trees the "resting diplotene" of winter was interrupted on one occasion and some male strobili had a "delayed meiosis" which occurred several days after meiosis in all other sampled strobili. Abnormal chromosome separations were observed on a few occasions; these consisted mostly of lagging chromosomes, a common abnormality in Larix meiosis. The implications for pollen development and seed yield are discussed.La microsporogénèse chez Larix laricina dans l'est de Terre-Neuve a été étudiée à intervalles hebdomadaires d'octobre à avril, pendant quatre années successives. Les strobiles mâles étaient fixés dans un mélange 3 : 1 d'éthanol – acide propionique, colorés au carmin alcoolique et écrasés dans l'acide acétique 45%.

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.

Chromosome studies on African plants. 9. Chromosome numbers in Ehrharta (Poaceae: Ehrharteae)

Bothalia ◽  
1989 ◽  
Vol 19 (1) ◽  
pp. 125-132 ◽  
Author(s):  
J. J. Spies ◽  
E. J. L. Saayman ◽  
S. P. Voges ◽  
G. Davidse
Keyword(s):  
Chromosome Number ◽  
Ploidy Level ◽  
Chromosome Numbers ◽  
Basic Chromosome Number ◽  
B Chromosomes ◽  
Basic Chromosome ◽  
Cytogenetic Studies ◽  
African Plants ◽  
First Time

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.

CHROMOSOME NUMBER, VOLUME AND NUCLEAR VOLUME RELATIONSHIPS IN A POLYPLOID SERIES (2X-20X) OF THE GENUS RUMEX

1971 ◽  
Vol 13 (4) ◽  
pp. 842-863 ◽  
Author(s):  
S. Ichikawa ◽  
A. H. Sparrow ◽  
C. Frankton ◽  
Anne F. Nauman ◽  
E. B. Smith ◽  
...  
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Abrupt Change ◽  
Diploid Species ◽  
Nuclear Volume ◽  
Polyploid Series ◽  
Unidentified Species

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.

Sign in / Sign up

Export Citation Format

Share Document