Cytological investigation of the Achillea millefolium complex (Compositae) in Quebec

1977 ◽  
Vol 55 (7) ◽  
pp. 796-808 ◽  
Author(s):  
Camille Gervais
Keyword(s):  
Chromosome Numbers ◽  
Pollen Grains ◽  
Achillea Millefolium ◽  
Root Tip ◽  
Herbarium Specimens ◽  
Cytological Investigation ◽  
Mitotic Abnormalities ◽  
Small Pollen ◽  
Tip Cells ◽  
Root Tip Cells

The study of the chromosome numbers of over 112 individuals belonging to the Achillea millefolium L. complex (Compositae) and the examination of the pollen of about 200 herbarium specimens have led to the following conclusions; the A. millefolium complex, in Quebec, includes tetraploids (2n = 36), hexaploids (2n = 54), and various hybrid types. Tetraploids could be divided into two taxa: the southernmost is A. lanulosa Nutt. with small pollen grains and light brown or yellowish-margined phyllaries while the northern or alpine plants, corresponding to A. nigrescens (E. Mey.) Rydb., possess large pollen grains and dark-margined phyllaries. The two species, in contact zones, seem to hybridize freely. Hexaploids comprise purple-flowered introduced individuals escaping from cultivation, white or pink individuals, also introduced, and possibly a native taxon. The introduced hexaploids belong to A. millefolium s.str. and the purple-flowered variety frequently hybridizes with A. lanulosa giving rise to pentaploids (2n = 45) apparently almost sterile. A few plants from Maine (U.S.A.) have also been studied. This paper finally reports cytological observations related particularly to spontaneous mitotic abnormalities (fragmentation, fusion of chromosomes) affecting root tip cells of seedlings.

scholarly journals Chromosome Number and Karyotype Variation in Codiaeum variegatum Cultivars

HortScience ◽  
2010 ◽  
Vol 45 (4) ◽  
pp. 538-540 ◽  
Author(s):  
Min Deng ◽  
Jianjun Chen ◽  
Richard J. Henny ◽  
Qiansheng Li
Keyword(s):  
Chromosome Numbers ◽  
Genetic Basis ◽  
Morphological Diversity ◽  
Root Tip ◽  
Limited Information ◽  
Ornamental Foliage Plants ◽  
Wide Range ◽  
Codiaeum Variegatum ◽  
Tip Cells ◽  
Root Tip Cells

Codiaeum variegatum (L.) Blume is one of the most popular ornamental foliage plants. It encompasses more than 300 recognized cultivars valued by their wide range of leaf shapes and vivid foliage colors. Thus far, only limited information is available regarding the genetic basis of their leaf morphological variation. This study investigated the chromosome numbers and karyotypes of seven phenotypically diverse cultivars. Root-tip cells were fixed, mounted, and observed under light microscopy. Results showed that chromosome numbers in the mitotic metaphase of the seven cultivars were high and variable and ranged from 2n = 66, 70, 72, 76, 80, 82, 84, to 2n = 96, indicating that the cultivars are polyploid and some could be aneuploid. Genetic mosaics occurred in one of the seven cultivars. Additionally, each cultivar had its own karyotype. There were no relationships between chromosome numbers or karyotypes and leaf morphology. Results from this study suggest that the morphological diversity among cultivars of this species could be in part attributed to high variation in chromosome numbers and karyotypes.

scholarly journals New chromosome numbers in Pilocarpus Vahl (Rutaceae)

2000 ◽  
Vol 14 (1) ◽  
pp. 11-24
Author(s):  
Ladislau A. Skorupa
Keyword(s):  
Chromosome Numbers ◽  
Room Temperature ◽  
Basic Number ◽  
Root Tip ◽  
Root Tips ◽  
Chromosome Counts ◽  
Pre Treatment ◽  
First Time ◽  
Tip Cells ◽  
Root Tip Cells

Chromosome counts for eight species of Pilocarpus Vahl (Rutaceae) a native of Brazil are reported for the first time. Chromosome numbers were determined from mitotic root tip cells of seedlings derived from field collections and grown in the greenhouse. Feulgen staining was used. Initial pre-treatment of root tips was done by using a saturated aqueous solution of alpha-bromonapthalene for two hours at room temperature (20-25ºC). Chromosome numbers of 2n=44 and 2n=88 were determined for the examined taxa. The present results suggest the occurrence of tetraploidy in P. spicatus St.-Hil. and P. carajaensis Skorupa, and a possible basic number x=22 to the genus Pilocarpus.

CYTOGENETICS OF 6X-AMPHIPLOID × AVENA SATIVA L. F1 HYBRIDS

1971 ◽  
Vol 13 (2) ◽  
pp. 292-297 ◽  
Author(s):  
R. A. Forsberg ◽  
S. Wang
Keyword(s):  
Avena Sativa ◽  
Seed Set ◽  
Pollen Grains ◽  
F1 Hybrids ◽  
Root Tip ◽  
Ploidy Levels ◽  
Sperm Nuclei ◽  
Mother Cells ◽  
Tip Cells ◽  
Root Tip Cells

Avena abyssinica (2n=28) × A. strigosa (2n=14) 6x amphiploids were crossed with 13 different A. sativa (2n=42) varieties or selections. There was considerable variation in chromosome number within and among F1 plants. The mode was 40 in root tip cells and 41 in pollen mother cells (PMC's). The number of univalents in PMC's ranged from 10 to 27 with a mean of 18.9. The average number of bivalents was 7.1, ranging from 2 to 13. Multiple associations were common. Only 10.8% of the pollen grains contained normally developed nuclei, i.e. one vegetative and two elongated sperm nuclei. Forty of 41 F1 plants were completely self-sterile and only one seed was obtained from 16,950 florets. Seed set in backcross pollinations with A. sativa was 1.25%, providing some opportunity for perpetuation of desirable genes from lower ploidy levels.

scholarly journals ANTIMITOTIC AND GENOTOXICITY EFFECTS OF WILD LIBYAN ARTICHOKE CYNARA CORNIGERA LEAVES AQUEOUS EXTRACT

2020 ◽  
pp. 448-454
Author(s):  
Yara El hasham ◽  
Fauzia El garabulli ◽  
Salem El shatshat
Keyword(s):  
Aqueous Extract ◽  
Chromosomal Aberrations ◽  
Leaf Extract ◽  
Root Meristem ◽  
Root Tip ◽  
Chromosomal Structure ◽  
Mitotic Abnormalities ◽  
And Behavior ◽  
Tip Cells ◽  
Root Tip Cells

Allium cepa root tip cells were used to find out the effect of Cynara cornigera extract on chromosomal structure and behavior during cell division. To measure the mitotic index and chromosome aberration in treated cells. The root meristem cells were treated with different concentrations of Cynara cornigera leaves aqueous extract (0.1, 0.01 and 0.001 mg/ml) for 4, 6 and 12 hours, respectively. The results indicate that aqueous extracts of C. cornigera plant have the ability to decrease the (MI) values with increasing the concentration at (P<0.005). The treatments have caused different kinds of mitotic abnormalities and chromosomal aberrations, such as: Change percentage of mitotic phases, C-metaphase, Stickiness, Disturbed nuclear membrane, Highly condensation of prophase and Accumulation of cell in interphase. KEY WORDS: Bioassay: Cynara cornigera: Leaf extract: Artichoke; Chromosomal aberrations.

SPONTANEOUS CHROMOSOME ABERRATIONS IN MELANDRIUM

1968 ◽  
Vol 10 (1) ◽  
pp. 143-147 ◽  
Author(s):  
Hiran C. Choudhuri
Keyword(s):  
Chromosome Aberrations ◽  
Pollen Grains ◽  
Root Tip ◽  
Dicentric Chromosomes ◽  
Ring Chromosomes ◽  
Melandrium Album ◽  
Spontaneous Chromosome ◽  
First And Second Generation ◽  
Tip Cells ◽  
Root Tip Cells

Chromosome aberrations were observed in root tip cells of Melandrium album. These aberrations were generally in the form of dicentric chromosomes involving bridge formation, ring chromosomes, fragments and elimination of acentric fragments from daughter nuclei. All the aberrations varied from 19.6 to 10.7 per cent in the first and second generation seedlings respectively. The chromosome irregularities and abortion of pollen grains (4.0 to 5.0%) are presumably due to gene mutation which has been enhanced in aged seeds.

REDUCTION OF CHROMOSOME NUMBER IN ROOT TIP CELLS OF MEDICAGO

1974 ◽  
Vol 16 (1) ◽  
pp. 219-227 ◽  
Author(s):  
R. S. Sadasivaiah ◽  
K. Lesins
Keyword(s):  
Chromosome Number ◽  
Ploidy Level ◽  
Chromosome Numbers ◽  
Plant Evolution ◽  
Root Tip ◽  
Aneuploid Chromosome ◽  
Tip Cells ◽  
Root Tip Cells ◽  
In Cells

Cytological studies on progenies obtained from intercrosses between colchicine-induced octoploid (2n = 8x = 64) plants of alfalfa showed normal, haploid and aneuploid chromosome numbers in cells of the same root tip. Critical observations on cells at different divisional stages revealed the occurrence of meiosis-like mitotic divisions, resulting in a reduction of chromosome number. The frequency of cells showing reductional divisions appeared to vary with the ploidy level of the material. The possible significance of chromosome reduction in plant evolution is indicated.

scholarly journals Cytogenetics of Mimosa bimucronata (DC.) O. Kuntze (Mimosoideae, Leguminosae): chromosome number, polysomaty and meiosis

2011 ◽  
Vol 11 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Denise Olkoski ◽  
Maria Teresa Schifino Wittmann
Keyword(s):  
Seed Set ◽  
Pollen Grains ◽  
Root Tip ◽  
Rio Grande Do Sul ◽  
Root Tips ◽  
Pollen Mother Cells ◽  
Species Area ◽  
Mother Cells ◽  
Tip Cells ◽  
Root Tip Cells

Chromosome numbers (somatic and/or gametic) were determined in 50 populations of M. bimucronata (DC.) O. Kuntze collected in the species area of distribution in Rio Grande do Sul, south Brazil. All populations were diploid (2n = 2x = 26, n = 13). Polysomatic (mostly tetraploid) cells were detected in the seedlings root-tip cells in 39 out of the 41 populations examined, ranging from 3.0 to 28.2 % among populations, but were absent in the root-tips of grown plants. Polysomaty was as well absent in pollen-mother cells. In M. bimucronata pollen-mother cells are joined two-by-two before the onset of meiosis, remaining attached during all the meiotic division until the formation of pollen grain polyads, composed of two sets of four pollen grains each, that are dispersed in this way, which, according to previous suggestions would be an adaptation to ensure high seed set after a single pollination event.

Short Communication. A robust method for chromosome quantification and ploidy determination in woody species

2009 ◽  
Vol 57 (2) ◽  
pp. 87 ◽  
Author(s):  
Harshi K. Gamage ◽  
Susanne Schmidt
Keyword(s):  
Light Microscopy ◽  
Chromosome Numbers ◽  
Nuclear Dna ◽  
Accurate Determination ◽  
Nuclear Dna Content ◽  
Root Tip ◽  
Root Tips ◽  
Ploidy Determination ◽  
Tip Cells ◽  
Root Tip Cells

Accurate determination of ploidy level of putative polyploid plants is essential for tree breeding and other applications. Methods for ploidy determination include quantification of chromosome numbers in root-tip cells via light microscopy and indirect assessment via anatomical and morphological traits. Flow cytometry is potentially a high-throughput method to quantify nuclear DNA content; however, it does not allow determining chromosome numbers and interfering compounds often prevent its use. Microscopy-based quantification of chromosomes in active root-tip cells remains the most unambiguous method for ploidy determination, although root tips are difficult to obtain from field-grown plants, and light microscopy can result in insufficient resolution in species with many and small chromosomes. Here, we present a robust technique that uses 2, 4-diamidino-2-phenylindole (DAPI) dye and 1000-fold magnification fluorescence microscopy for quantification of chromosomes in root and shoot tips of woody angiosperms and gymnosperms, and overcomes the reported difficulties. Rather than the conventional tip squashing, spreading tips on glass slides resulted in very good chromosome separation in diverse species, with up to 56 chromosomes and a chromosome size of 2–20 μm. Chromosome counts were performed in diploid Agathis robusta, Elaeocarpus angustifolius, Eucalyptus robusta, Paulownia tomentosa, Pongamia pinnata and Toona ciliata, and di- and tetraploid Acacia crassicarpa and Citrus species.

scholarly journals Morphological Characterization of Three Intergeneric Hybrids Among Gloriosa superba ‘Lutea’, Littonia modesta, and Sandersonia aurantiaca (Colchicaceae)

HortScience ◽  
2008 ◽  
Vol 43 (1) ◽  
pp. 115-118 ◽  
Author(s):  
Junji Amano ◽  
Sachiko Kuwayama ◽  
Yoko Mizuta ◽  
Masaru Nakano ◽  
Toshinari Godo ◽  
...  
Keyword(s):  
Morphological Characteristics ◽  
Pollen Grains ◽  
Morphological Characterization ◽  
Intergeneric Hybrids ◽  
Root Tip ◽  
Gloriosa Superba ◽  
Hybrid Plants ◽  
Tip Cells ◽  
Root Tip Cells

Three intergeneric hybrids among colchicaceous ornamentals, Gloriosa superba ‘Lutea’ (2n = 2x = 22), Littonia modesta (2n = 2x = 22), and Sandersonia aurantiaca (2n = 2x = 24), were subjected to morphological characterization and chromosome observation. Hybrid plants produced flowers 2 to 3 years after transplantation of ovule culture-derived plantlets to the greenhouse. All the hybrid plants, L. modesta × S. aurantiaca, L. modesta × G. superba ‘Lutea’, and S. aurantiaca × G. superba ‘Lutea’, showed a climbing habit like those of L. modesta and G. superba ‘Lutea’. Plants of L. modesta × S. aurantiaca and L. modesta × G. superba ‘Lutea’ were taller and shorter than their respective parents, whereas plant height of S. aurantiaca × G. superba ‘Lutea’ was nearly intermediate between the parents. Leaves of all the hybrids had a tendril at the tip like those of L. modesta and G. superba ‘Lutea’. Flower morphologies of all the hybrids were nearly intermediate between the parents. Flower colors of all the hybrids were similar to the seed or pollen parent. Although hybrids of L. modesta × G. superba ‘Lutea’ showed low pollen fertility as assessed with acetocarmine staining, the other two kinds of hybrids had nondehiscent anthers or no fertile pollen grains. Chromosome observation in root tip cells revealed that all the hybrids had a diploid number of chromosomes: L. modesta × S. aurantiaca (2n = 2x = 23), L. modesta × G. superba ‘Lutea’ (2n = 2x = 22), and S. aurantiaca × G. superba ‘Lutea’ (2n = 2x = 23). Novel morphological characteristics of the hybrids may be valuable for future breeding of colchicaceous ornamentals.

Sign in / Sign up

Export Citation Format

Share Document