Showing papers in "Cytologia in 1989"
TL;DR: DNA-content of nuclei from pollen was determined using flow cytometry, finding that the different C-levels, representing the DNA-contents of the generative and vegetative nuclei in G1 and G2 phase respectively, can be related to haploid and diploid pollen.
Abstract: DNA-content of nuclei from pollen was determined using flow cytometry The pollen from diploid genotypes gave rise to a 1C- and a 2C-peak of identical size, representing the vegetative and the generative nuclei Pollen of the interspecific hybrid (L auratum×L henryi) presented only 2C- and 4C-peaks, while in the interspecific hybrids (LבEnchantment’×Lpumilum) 1C-, 2C- and 4C-peaks were distinguished The different C-levels, representing the DNA-contents of the generative and vegetative nuclei in G1 and G2 phase respectively, can be related to haploid and diploid pollen Results of a meiotic analysis, a number of crossing experiments and pollen measurements agreed with the outcome of the flow cytometric determinations The flow cytometry method enables the large scale screening of collections of genotypes for their potential of 2n-pollen production
72 citations
57 citations
TL;DR: The effect of Garlon-4 on root mitosis simulates that of colchicine in the type of abnormal meta- and anaphases and the induction of polyploid cells as well as accumulation of metaphases.
Abstract: The effect of the herbicide (Garlon-4) has been studied on root mitosis of Allium cepa (v. Giza-6). It contains triclopyr as an active ingredient and its chemical formula is 3, 5, 6 trichloro-2-pyridinyloxy-acetic acid. Root tips of Allium cepa were treated with a series of concentrations, ranging from 28ppm to 38400ppm for 3, 6, 12 and 24 hours. Examination of the roots was done in permanent root tip squash preparations stained by the Feulgen technique. Garlon affects the relative duration of each mitotic stage as compared with the control. It also caused reduction in mitotic index, indicating mitotic inhibition, and increase in the frequency of abnormal mitoses, the precentages of which are highly significant, except the lowest concentration (28ppm) which had no significant effect after 6 hours and induced a statistically significant percentage of abnormal mitoses from the control after 12 hours of the treatment.The types of abnormalities induced included: chromosome stickiness, c-metaphase, canaphase, tetraploid and restitution nucleus, star metaphase, laggards, bridges, tripolar, and disturbed meta- and anaphases. Micro- and binucleate cells as well as multinucleated cells at the interphase stage were also observed.The effect of Garlon-4 on root mitosis simulates that of colchicine in the type of abnormal meta- and anaphases (c-metaphase and c-anaphase) and the induction of polyploid cells as well as accumulation of metaphases.
55 citations
TL;DR: The cytogenetic effects of sodium salicylate were investigated in the root meristem cells of Allium sativum L and induced a significant increase in nuclear and chromosomal aberrations.
Abstract: The cytogenetic effects of sodium salicylate were investigated in the root meristem cells of Allium sativum L. Young roots were treated with 0%, 0.05%, 0.1%, 0.25%, 0.5%, 0.75% and 1% aqueous solutions of sodium salicylate for 2, 4, 6 and 8 h periods. Aberrations and dividing cells were determined from the root-tip squashes after a 24h recovery period. Sodium salicylate induced a significant increase in nuclear and chromosomal aberrations. This increase was dependent on both the treatment duration and the concentration of sodium salicylate. The observed aberrations consisted of micronuclei and fragments, nuclear degeneration, chromosome breakage, stickiness of chromosomes, spindle abnormalities, binucleate and polyploid cells. Sodium salicylate was also found to act as a mitodepressant.
32 citations
TL;DR: Chromosome counts for three species and two varieties of Japanese Fragaria were determined, and the first report of the chromosomes of F. nipponica var.
Abstract: Chromosome counts for three species and two varieties of Japanese Fragaria were determined. This is the first report of the chromosomes of F. nipponica var. yakusimensis. Fragaria nipponica var. nipponica, F. nipponica var. yakusimensis, F. nipponica var. yezoensis and F. vesca were very similar in karyotype morphology, but F. iinumae showed differences from those taxa.
30 citations
TL;DR: The absence of wide differences in nuclear DNA content in the varietal level indicate a close relationship between Coriandrum sativum L. and 4C, which have played a vital role in intervarietal DNA variation.
Abstract: Extensive karyological analysis including determination of somatic chromosome number, total chromosome length and volume and estimation of 4C DNA amount were carried out on 8 different varieties of Coriandrum sativum L. A significant variation in nuclear DNA amount was recorded in the varietal level. The structural alteration of chromosome as well as loss or addition of highly repetitive sequences in the genome have played a vital role in intervarietal DNA variation. The absence of wide differences in nuclear DNA content in the varietal level indicate a close relationship between them.
26 citations
TL;DR: Karyotype analysis of three varieties of Indian fennel revealed that minute structural alteration of chromosomes associated with variation of 4C DNA content, genomic chromosome length and genomic chromosome volume has played an important role in establishment of new cultivated varieties.
Abstract: Karyotype analysis of three varieties of Indian fennel (Foeniculum vulgare Mill.) revealed that minute structural alteration of chromosomes associated with variation of 4C DNA content, genomic chromosome length and genomic chromosome volume has played an important role in establishment of new cultivated varieties.
25 citations
TL;DR: Detailed microsporogenesis of hexaploid Morus serrata has been studied and diploid like behaviour of this species with high frequency of bivalents, regular meiosis and high pollen stainability are discussed in relation to its evolution.
Abstract: Detailed microsporogenesis of hexaploid Morus serrata has been studied. This is the first record of natural hexaploidy (2n=6x=84) in the species. Meiosis has been found regular with high frequency of bivalents. The frequency of hexa-, penta-, tetra- and trivalents is considerably less suggesting its allopolyploid nature. Diploid like behaviour of this species with high frequency of bivalents, regular meiosis and high pollen stainability are discussed in relation to its evolution.
24 citations
22 citations
TL;DR: The PMCs of triploid hybrid showed strikingly different aspects in meiosis from those of diploid hybrids; homologous chromosomes of C. esculenta formed bivalents, while chromosomes ofC.
Abstract: Cytogenetical studies were carried out on the artificial F1 hybrids between Colocasia esculenta (2n=28) and C. gigantea (2n=28). Of 15 individuals 14 possessed 2n=28, the diploid level of x=14, while 1 of 15 showed 2n=42, the triploid level.The diploid hybrids contained two chromosome sets, one from each parental species. In spite of the similar morphology of chromosome complements to each other parental species, the PMCs of the diploid hybrids showed an abnormal feature in meiosis; almost all chromosomes formed univalents. This abnormal pairing form resulted in the complete sterility of its pollen grains.The triploid hybrid contained two chromosome sets from C. esculenta and one set from C. gigantea. The PMCs of triploid hybrid showed strikingly different aspects in meiosis from those of diploid hybrids; homologous chromosomes of C. esculenta formed bivalents, while chromosomes of C. gigantea formed univalents. The rate of good pollen grains increased to 21%.
20 citations
TL;DR: The organophosphorus insecticide malathion should be viewed as a potentially genotoxic agent, particularly for those who come in contact with the compound repeatedly, particularly at the higher concentrations.
Abstract: The organophosphorus insecticide malathion is extensively used in commercial and agricultural control of insects. The potential of the compound as a genotoxic agent was determined on the basis of chromosome damage and rates of sister chromatid exchanges in human lymphocyte culture. Four treatments (5, 20, 40 and 50μg/ml), a solvent control and an untreated control were used in three replications for 4-hr and 24-hr exposures to assess the damage to chromosomes. Three treatments (5, 20 and 50μg/ml) and the solvent control, in one replication, were used to determine the rates of sister chromatid exchanges. A trend of higher rates of chromosomal aberrations was observed reaching statistical significance generally at the higher concentrations. The sister chromatid exchange rates were highly significantly elevated at 20μg/ml or higher concentration. Malathion therefore should be viewed as a potentially genotoxic agent, particularly for those who comein contact with the compound repeatedly.
TL;DR: A chromosome polymorphism due to Robertsonian fusion is present in this species of Gobius niger jozo.
Abstract: By analysing chromosome preparation from 42 Gobius niger jozo specimens from the Gulf of Palermo (Sicily), four different karyotypes were observed: A (2n=52; NF=60), B (2n=51; NF=60), C (2n=50; NF=60) and D (2n=49; NF=60). A chromosome polymorphism due to Robertsonian fusion is present in this species.
TL;DR: Triploids were successfully evolved in mulberry by diploidizing female gamete cells of Morus alba var.
Abstract: Triploids were successfully evolved in mulberry by diploidizing female gamete cells of Morus alba var. Kanva-2 with 0.2%, 0.3% and 0.4% colchicine treated for 8 hours for consecutive 3 days and by crossing them with monoecious diploid mutant. The triploids are characterized by increased growth and rooting habit; weight, size and water content of leaves, size of stomata and number of stomatal chloroplast and reduction in frequency of stomata per unit area and internodal distance have been recorded. Meiosis is highly irregular and characterized by the presence of a high frequency of trivalents and univalents. Various types of chromosomal associations, presence of tetravalents, unequal distribution and precocious movements of chromosomes, laggards, bridges at metaphase I and II, cytomixis at metaphase I and II, telophase I and II, dyads and tetrads stages and varying number of microspores have been frequently observed in the PMCs. The reduced pollen fertility has been attributed to various meiotic anomalies. Maintenance and commerical exploitation of triploids with desirable characters on large scale is feasible by vegetative multiplication.
TL;DR: All the three salts of nickel viz. nickel chloride, nickel nitrate and nickel sulfate induced micronuclei in the polychromatic erythrocytes of mice and caused various types of abnormalities in the head of spermatozoa.
Abstract: All the three salts of nickel viz. nickel chloride, nickel nitrate and nickel sulfate induced micronuclei in the polychromatic erythrocytes of mice. These also caused various types of abnormalities in the head of spermatozoa. The frequency of spermatozoa with abnormal heads was maximum with nickel nitrate.
TL;DR: It has been revealed from the present investigation that U. coromandeliana is not an exact multiplication of chromosomes of U. indica, but segmental polyploid of hybrid origin, and the geographical isolation, ecological factors, chromosomal repattering, hybridization and ploidy level seem to be responsible for morphological diversity in U.
Abstract: This paper deals with cytomorphological studies in Urginea indica Kunth. (2n=20) and U. coromandeliana (Roxb.) Hook. f. (2n=40). It has been revealed from the present investigation that U. coromandeliana is not an exact multiplication of chromosomes of U. indica, but segmental polyploid of hybrid origin. The geographical isolation, ecological factors, chromosomal repattering, hybridization and ploidy level seem to be responsible for morphological diversity in U. coromandeliana and support Hooker's (1892) recognition as a separate species. Experimental interspecific hybridization in Urginea species indicated the close interrelationship between U. indica, U. polyantha, U. govindappae and U. coromandeliana, and ‘Weak’ incompatibility reaction between U. indica and U. razii, U. coromandeliana and U. razii and distant relationship of U. congesta with other species of Urginea under investigation.
TL;DR: Comparative karyomorphological analysis of 21 types belonging to nine species of Capsicum revealed conspicuous intra- as also inter-specific variations, which suggests relatively symmetrical karyotypes in wild and semiwild species probably due to highly restricted distribution within the narrow ranges around centre of origin.
Abstract: Comparative karyomorphological analysis of 21 types belonging to nine species of Capsicum revealed conspicuous intra- as also inter-specific variations. All types had 2n=24 chromosomes though they differ in the number of SAT-chromosomes. Total length of the complement was maximum in pubescens and minimum in testiculatum. Difference in longest and shortest chromosomes of a complement was highest in pendulum. Number of homobrachial chromosomes was more in wild and semiwild species whereas in cultivated species heterobrachial chromosomes were relatively more. Overall consideration of these observations suggests relatively symmetrical karyotypes in wild and semiwild species probably due to highly restricted distribution within the narrow ranges around centre of origin. On the contrary, cultivated species cover extensive areas and wide ranges of ecological habitats, resulting in relatively asymmetrical karyotypes.
TL;DR: The auto- or allopolyploid nature of these species was discussed basing on the meiotic behaviour of the cytotypes examined, and it was inferred that P. mezianum, P. divisum and P. orientale are autotetraploids while P. setaceum is an allotriploid.
Abstract: Meiosis was studied in twelve species of Pennisetum covering three basic chromosome numbers viz. x=7, 8 and 9. Except P. americanum, P. violaceum and P. hohenackeri all others were found to be polyploids. The auto- or allopolyploid nature of these species was discussed basing on the meiotic behaviour of the cytotypes examined. It is inferred that P. mezianum, P. divisum and P. orientale are autotetraploids while P. setaceum is an allotriploid, P. purpureum and P. clandestinum tetraploids, P. villosum an allopentaploid and P. squamulatum and P. polystachion allohexaploids. The possible causes for the stabilization of these species suggested.
TL;DR: The karyotypes and chromosome configurations in the F1-hybrids between Chrysanthemum lavandulaefolium var.
Abstract: 1. The karyotypes and chromosome configurations in the F1-hybrids between Chrysanthemum lavandulaefolium var. sianense from China and Ch. boreale from Japan were investigated.2. The karyotype of sianense is more primitive than that of boreale, because sianense has more symmetrical karyotype and more satellite chromosome than boreale. Therefore, it is assumed that sianense is a primitive species in genus Chrysanthemum.3. In spite of the small difference in the karyotypes of both species, the genomes of both species are almost homologous because of the high rate of homomorphic bivalent formation in their F1-hybrids.
TL;DR: The cytological changes produced by magenesium sulphate were studied in root meristems of Vicia faba and revealed the cytostatic and clastogenic properties of magnesium sulphate.
Abstract: The cytological changes produced by magenesium sulphate were studied in root meristems of Vicia faba. Roots treated with different concentrations of magnesium sulphate showed the presence of chromosome breakage, achromatic lesions, chromosome clumping, lagging chromosomes, micronuclei etc. Spindle abnormalities leading to the formation of polyploidy and aneuploidy were also observed. Magnesium sulphate exerted mitodepressive effects in higher concentrations. The present studies have revealed the cytostatic and clastogenic properties of magnesium sulphate.
TL;DR: Cytological studies have been carried out on four different species of Agave, distributed in different parts of India, and clear absence of distinct multiples in the karyotypes rules out the absence of autopolypoloidy.
Abstract: Cytological studies have been carried out on four different species of Agave, distributed in different parts of India. They revealed triploid to hexaploid numbers ranging from 2n=90 to 180. A distinct bimodal karyotype with very long and very short chromosomes in a definite proportion of 5:25 ratio and a constant base number of n=30 chromosomes are the most significant characteristics. However, structural alterations, principally involving the nucleolar chromosomes of both long and short types, have been recorded. Clear absence of distinct multiples in the karyotypes rules out the absence of autopolypoloidy. Total chromosome length and volume do not necessarily represent direct multiplication along with the multiplication of the chromosome number. All these factors suggest the role of structural alterations along with differential degrees of coiling of chromosomes and allopolyploidy rather than autopolyploidy in the evolution of the different taxa.
TL;DR: The comparative analysis of data indicates that colonising species possess besides dynamic breeding mechanisms like vegetative, selling and outcrossing, a significantly higher chiasmata/bivalent resulting in high frequency of gene reshuffling.
Abstract: To determine the cytogenetical basis of breeding systems, detailed vegetative and floral features along with the chiasmata/nucleus/bivalent have been investigated in two successful colonising species Lippia nodiflora and L. geminata. These attributes have been compared with those in two non-colonising ornamentals, Verbena hybrida and V. bonariensis. The comparative analysis of data indicates that colonising species possess besides dynamic breeding mechanisms like vegetative, selling and outcrossing, a significantly higher chiasmata/bivalent resulting in high frequency of gene reshuffling. The ornamentals on the other hand have only sexual mode of breeding, mostly outcrossing, and lower chiasmata per bivalent. This differential behaviour between the two groups of species enables the colonisers to thrive in adverse ecological niches under rigorous natural selection whereas the ornamentals thrive only under human care and nurture.
TL;DR: The presence of associations with more than two chromosomes in Zephyranthes sp.
Abstract: The karyotype of five species of the genus Zephyranthes Herb. was analyzed: Z. aff. mesochloa, 2n=12; Z. aff. stellaris, 2n=20; Zephyranthes sp. (accession 1), 2n=30 and 2n=31; Zephyranthes sp. (accession 3), 2n=40 and Zephyranthes sp. (accession 4), 2n=50. The karyotype found in the five species studied is in general symmetric except for Z. aff. mesochloa. Chromosome pairing at metaphase I of three species was studied. The results showed that Zephyranthes sp. (accession 1) and Zephyranthes sp. (accession 4) are allopolyploid and that a new basic number in the genus might well be x=5. The presence of associations with more than two chromosomes in Zephyranthes sp. (accession 4) suggests that this species is a segmental allopolyploid since the genomes which participated in their origin are homoeologous.
TL;DR: Caryotypes de Salvia amarissima, S. fluviatilis,S.
Abstract: Caryotypes de Salvia amarissima, S. fluviatilis, S. hispanica, S. longispicata et S. tiliifolia
TL;DR: The present communication puts on record the chromosome behaviour during reduction division in the pollen mother cells of 21 diploid species of Astragalus, growing wild in the Kashmir Himalaya, and points out that there is a positive correlation between the recombination indices and the total chromatin lengths in these species.
Abstract: The present communication puts on record the chromosome behaviour during reduction division in the pollen mother cells of 21 diploid species of Astragalus, growing wild in the Kashmir Himalaya. In all these species meiosis was by and large normal. The occasional segregational anomalies, observed in a few species, have also been described. The low frequency of PMCs with these anomalies indicate that these are not due to any genetic change but can be explained on the basis of occasional segregational errors only. It has been pointed out that there is a positive correlation between the recombination indices and the total chromatin lengths in these species.
TL;DR: Hutchinson's treatment of Cordyline and Dracaena along with Sansevieria and Cohnia in the same tribe (Dracaeneae) is pointed out to be justifiable on karyological grounds, and this supports the suggested removal of Dracaenesae from the Agavaceae.
Abstract: Cytology of three species of Cordyline and ten of Dracaena is reported from South India. The gametic numbers observed in species of Cordyline is n=19 and in Dracaena are n=18, 19 and 20, of which n=19 predominated.Chromosome data show that both the genera have similar basic chromosome consitution (x=18, 19, 20) and small sized chromosomes. The x=20 in Dracaena is postulated to be the earlier evolved one by polyploidy from a possible x=10 primary condition.Polyploidy and aneuploidy appear to have played significant role in speciation and evolution in the genus.Systematic relationships of the genera is considered. Hutchinson's treatment of Cordyline and Dracaena along with Sansevieria and Cohnia in the same tribe (Dracaeneae) is pointed out to be justifiable on karyological grounds. But this tribe appears to have very little cytological likeness with the other tribes of Hutchinson's Agavaceae, and this supports the suggested removal of Dracaeneae from the Agavaceae.
TL;DR: The karyotype study revealed that chromosomes were small and asymmetrical, and microspore mother cells of all species was almost similar except A. pinnata (Vietnam), which was a triploid.
Abstract: The somatic chromosome numbers (2n) were 48, 40, 44, 44 and 66 respectively in A. mexicana, A. filiculoides, A. pinnata Aftrica, A. pinnata Cuttack, India and A. pinnata (green isolate, Vietnam). The karyotype study revealed that chromosomes were small and asymmetrical. The total chromatin length (TLC) was employed as an index of species delimitation. Basing on absolute length (AL) the chromosomes were grouped into different sets and karyotypic formula was established for each species.Meiotic behaviour of microspore mother cells (SMC) of all species was almost similar except A. pinnata (Vietnam) and A. filiculoides. In all cases microspore mother cells (SMC) exhibited many common features. Usually quarterets of SMC were observed on pressing. Vacuolisation put the cytoplasm more clear during early prophase and gradual granulation brought more stainability in later stages. Marginal orientation of chromatic materials was noticed. Multivalents were observed in A. pinnata (Vietnam). In A. filiculoides, deformed spindle and unequal spore formation were noticed in some of the SMC. In A. pinnata (Vietnam) almost all spores were much smaller in size. A. mexicana, A. pinnata (India), A. filiculoides and A. pinnata (Africa) were considered to be true diploids whereas A. pinnata (green isolate, Vietnam) was a triploid.
TL;DR: Cytotoxic threshold dose of three commonly used pesticides was determined using relative division and abnormality rates in meristematic cells of Allium cepa root tip by using dose-response curves populated with varied number of smaller doses.
Abstract: Cytotoxic threshold dose of three commonly used pesticides (Malathion, Metacid and Lindane) was determined using relative division and abnormality rates in meristematic cells of Allium cepa root tip by using dose-response curves populated with varied number of smaller doses. The results obtained show such dose to be 25, 20 and 50 ppm for Malathion, Metacid and Lindane respectively.
TL;DR: Karyotype study shows close affinity between this species and the cosmopolitan C. lacryma-jobi and its chromosome number is found to be n=20 and 2n=40 which is a new count for this species.
Abstract: C. aquatica could be clearly distinguished on the basis of habit, by the presence of glands which bear bristle-like hairs in the upper surface of the levaes and leaf-sheaths and the involucre which is abruptly constricted into a beak. Its chromosome number is found to be n=20 and 2n=40 which is a new count for this species. Meiosis is normal and this is a highly stabilized species which propagates by seeds as well as by suckers. Karyotype study shows close affinity between this species and the cosmopolitan C. lacryma-jobi.