The effects of the food preservatives potassium metabisulphite (PMB) and potassium nitrate (PN) have been studied on root tips of Allium cepa L. (variety Kantartopu-3). Roots of A.cepa were treated with a series of concentrations, ranging from 50 ppm to 100,000 ppm for 3, 6, 12, 24 and 48 h. Examinations of roots were done in permanent root tip squash preparations stained by the Feulgen technique. PMB and PN effect on the relative duration of each mitotic stage as compared with the control. They are also caused reduction in the mitotic index, indicating mitotic inhibition and increased frequency of abnormal mitosis. The type of abnormalities induced are chromosome stickiness, c-metaphase, anaphase and telophase bridges, disturbed chromosomes of anaphase and telophase stages, anaphase lagging and forward chromosomes at anaphase and telophase and micronuclei formation at intephase cells.
This paper presents the chromosomal number of 18 species of Bromeliaceae occurring in Brazil, which belong to the Neoregleia, Cryptanthus, Canistropsis, Canistrum, Hohenbergia, Orthophytum and Witrockia genera. The results display the 2n=50 diploid number for the majority of the species, 2n=34 for the Cryptanthus species and 2n=100 for Orthophytum amoenum. B chromosomes were observed in Hohenbergia pennae. This is the first register for 14 species and the new counting for Neoregelia carolinae, Neoregelia cruenta, Canistropsis microps and Cryptanthus beuckeri. The chromosomal counting in this work agree with the basic number x=25 for the majority of the species and x=17 for the Cryptanthus ones.
Lumigan® (Bimatoprost) is a new eye drop that combats high pressure inside the eye. It is prescribed for a condition called open-angle glaucoma (a gradual increase of pressure in the eye). It lowers pressure by promoting drainage of the excess of the intraocular fluid. The effects of Lumigan during pregnancy have not been adequately studied. Therefore, the present study aims to evaluate the cytogenetic and developmental effects of Lumigan on the mothers and their fetuses. Lumigan was administered orally to pregnant mice at doses of (0.05, 0.2, 0.3 and 0.6 mg/kg/d) (approximately equal and more than 10 times the recommended human dose) from 1 to 18 d of gestation. Females were killed on day 19 gestations and examined for evidence of fetal toxic signs and cytogenetic effects. Lumigan at different doses did not produce any significant adverse effects in reproductive parameters. Significant embryotoxic effects were not observed at the tested dose levels up to 10 times the recommended dose. The total number of implantations, post-implantation loss and fetal weight were not significantly affected compared with the controls. There were no major malformations in the fetuses compared with the controls. In addition, Lumigan was found to be non-genotoxic to the mothers and embryos in the micronucleus and chromosomal aberration analyses. Therefore, Lumigan is considered to be safe during pregnancy.
One partial asynaptic mutant of Vicia faba (2n=12) was isolated from M2 population of 0.2% EMS (Ethyl Methane Sulphonate) treated seeds. The mutant was designated as ‘medium strong asynaptic mutant’. At diakinesis/metaphase I of meiosis number of univalents ranged from 2–8 in 90% of PMCs in M2 and 2–4 in 44% of PMCs in M3. There was a significant decrease in the number of chiasmata in this plant as compared to the control. The metacentric chromosome pair did not show univalence. The pollen fertility was also reduced by 35%. The inheritance of this asynaptic mutant was probably of monogenic recessive type.
Meiotic analysis performed in O. basilicum L. (2n=72) and O. tenuiflorum L. (2n=36) demonstrated persistent presence of secondary association of chromosomes in 94.74 and 85.16 per cent metaphase I cells respectively. Secondary polyploidy has been attributed as the possible cause of secondary association of chromosomes and the basic chromosome number for both species has been suggested to be x=12 with probable origin from primitive base number x=6 through polyploidy.
In vitro response of interaction of various growth regulators and explants was studied in Trifolium apertum (genotype EC 401712), a diploid species domesticated in Russia. The species is considered as a progenitor of T. alexandrinum, a very important fodder legume cultivated in Indian sub-continent. The callus induction was found to be dependent on level of growth regulators, auxin and cytokinin ratio and the explants. Medium ‘A’ with low level of growth regulators failed to induce callus in 5 out of 6 explants. High hormone medium ‘D’ showed good callogenesis in hypocotyl, cotyledon and petiole explants. In collar, leaf and root explants the frequency of callus induction was very low. Friable green calli were observed in hypocotyl and petiole explants. The high auxin: cytokinin ratio favoured callus induction. NAA in high concentration was found to be better than Picloram as auxin source. The differences in callus induction frequency were found to be statistically significant for both explant and media as well as their interaction. The calli from petiole explant-‘D’ medium combination showed very good organogenetic and embryogenetic potential on sub-culture. 50% of sub-cultures showed shoot induction and a large number of them showed root induction in rooting media. A suitable protocol for regeneration and transfer of plantlets in vitro in this genotype of T. apertum has been developed for first time. The cytology of the plants revealed normal meiotic pairing with 8 bivalents.
Chromosomal analysis of 4 Egyptian species of family Buthidae (Androctonus australis, Androctonus bicolor, Androctonus amoreuxi and Androctonus crassicauda) have been studied. The 4 buthid scorpions species have the same diploid chromosome number of 2n=24. These species have a unique combination of cytogenetic features including holocentric chromosomes. Multivalent chromosomes of regular and irregular form were observed during the first meiotic division. To the best of the authors knowledge, these results are reported for the first time in Egypt.
Cytological investigation was conducted on Vigna subterranean (L.) Verdc. using root squash technique. Apices of root tips pretreated for 3 h with 2 mM 8-hydroxyquinoline, fixed for 24 h with 1 : 3 acetic ethanol (aq.), and hydrolised with 10% HCl were squashed in drops of FLP orcein on clean glass slides. Slides were examined under a Leitx Diaplan research microscope and micrographs of good cells were obtained using Leica WILD MPS microscope camara fitted with a photoautomat. A chromosome number of 2n=22 was recorded for the taxon. The chromosomes varied from metacentric to submetacentric. This is the first report of the karyotype of this species.
Preliminary isolation of viable protoplasts from egg cells was carried out using 3 enzyme treatments followed by mechanical manipulation from ovaries of facultative apomictic Panicum maximum. Incubation of ovaries staged at anthesis for up to 6 h allowed the boundary wall of the reproductive cells to become completely digested protoplasts in individual. The egg protoplasts cultured on appropriate medium formed complete cell wall after 2 d of culture, indicating the protoplast's strong viability. The same kinds of ovaries were analyzed with Nomarski differential interference contrast microscopy, indicating sizes and morphologies of the cells corresponded to those of isolated protoplasts. Isolation of egg cell and in vitro fertilization could be useful to clarify the mechanism of reproductive process in apomictic P. maximum.
The chromosomes of ten species of birds and their karyological relationships have been studied. These species are Gelochelidon nilotica 2n=60 and Larus genei 2n=54 (Family: Laridae), Himantopus himantopus 2n=58 (Family: Recurvirostridae), Hoplopterus spinosus 2n=72 (Family: Charadriidae), Lophura edwardsii 2n=50 (Family: Phasianidae), Numida meleagris 2n=56 (Family: Numididae), Tachybaptus ruficollis 2n=58 (Family: Podicipedidae), Phalacrocorax carbo 2n=62 (Family: Phalacrocoracidae), Plegadis falcinellus 2n=50 (Family: Threskiornithidae) and Anas querquedula 2n=74 (Family: Anatidae).
Influence of various fruit-derived explants and different genotypes on induction of somatic embryogenesis in black pepper was studied. Among the various explants cultured on plant growth regulator-free solid SH medium maintained in dark, the ‘abortively germinated seeds in vitro’ produced the highest percent response as well as number of somatic embryos per responded explant. Lowest percent response and frequency of somatic embryos were evident with the ‘unripened green fruits with zygotic embryo removed’. Zygotic embryos as such failed to produce any somatic embryogenic response. Of the various genotypes tested, cultivar ‘Karimunda’ was found to be highly embryogenic and cultivar ‘Kutching’ was totally non embryogenic. Other cultivars showed variable degree of embryogenic response.
The ploidy levels of the in vitro and the in vivo plants of T. roxburghianum were invariably tetraploid (2n=4x=44). The chromosome number of calli were 2n=2x=22 and 2n=8x=88, amidst the normal chromosome number of 2n=4x=44. Changes in the chromosome length, disparity index, variation coefficient and total forma percentage were noticed. The diakinesis and metaphase stages of the in vitro flower showed quadrivalents among bivalents, whereas the same stages of the in vivo plant showed bivalents only.
Chromosomes in prometaphases and typical metaphases obtained from root meristems of samples of Crotalaria incana, collected in the Mexican municipalities of Tamasopo (San Luis Potosí) and Martínez de la Torre (Veracruz) were analyzed, paying special attention to the possible cytotypic variation due to differences in number and nature of the chromosomes with secondary constrictions and satellites. The chromosomal number 2n=14 (in both populations), the great uniformity in the total haploid chromosomal length, the karyotypic formula (8 m+6 sm), the chromosomal length interval, and a slight difference in the asymmetry index were corroborated with the use of the “air drying method” (splash). It was observed that the 14 chromosomes, particularly in prometaphase, exhibit uncoiled terminal regions which could be confused with secondary constrictions. These findings are compared to previous records on the fine chromosome morphology of C. incana and other species of the genus. The existence of proposed cytotypes for the species is discarded, and their evolution as a function of gene changes or genic complexes is discussed.
The Andaman-Nicobar group of Islands is located in the Bay of Bengal between the Indian subcontinental and the Thailand-Malaysia-Indonesia region. A Saccharum spontaneum L. clone was collected from the Car-Nicobar Island during a germplasm-exploration conducted in the Island in March 2003. This is the first collection of S. spontaneum from the Island. The chromosome number of this clone was examined in relation to the distribution of different cytotypes of S. spontaneum in the region. The somatic chromosome number of the clone was found to be 2n=88, which is not a common cytotype in the neighbouring areas including the Indian subcontinent and the Indonesian archipelago. The possibility of its origin through the natural hybridisation between 2n=80 and 96 forms of S. spontaneum is discussed. Cytotypes with 2n=80, 96 and 88 chromosomes are present in Thailand and it is likely that this clone originated in Thailand and spread to Car-Nicobar subsequently.
In the present study effects of the polyamines; putrescine (Put), spermidine (Spd) and spermine (Spm) have been studied on root tip mitosis of Allium cepa L. Root tips of A. cepa were treated with a series of polyamine (PA) concentrations, ranging from 0.01, 1 and 2 mM for 3, 6, 12, 24 and 48 h. The roots were examined in permanent root tip squash preparations stained by the Feulgen technique. This research has confirmed that PAs have various effects on chromosomes. PA concentrations used, generally had a marked mitodepressive effect on mitotic index (MI) but at 6 h treatment of Spm, Spd and Put at all concentrations had increased MI. Polyamines affected the relative duration of each mitotic stage as compared to the control. They also increased frequency of abnormal mitosis. The types of abnormalities induced are: chromosome stickiness, c-metaphase, anaphase and telophase bridges, disturbed chromosomes of anaphase and telophase stages, lagging and forward chromosomes at anaphase and telophase. Binucleate cells and micronuclei formation at interphase cells were also observed.