Showing papers in "Cytologia in 1976"
45 citations
TL;DR: Extracts of fresh rhizomes of Zingiber officinale (ginger) and Curcuma longa (turmeric) are radiomimetic and may be mutagenic and the predominant type of aberration was chromosome breakage.
Abstract: The effects of the two commonly used condiments, ginger and turmeric on cell divisions in root tip cells of onion have been studied. The predominant type of aberration in both cases was chromosome breakage. C-mitosis, somatic segregations, multipolar anaphases etc. were also observed. The present study has shown that extracts of fresh rhizomes of Zingiber officinale (ginger) and Curcuma longa (turmeric) are radiomimetic and may be mutagenic.
28 citations
TL;DR: The distribution of G-bands in three Akodon species is analysed in order to gain a further insight into the problem of interspecific chromosome homo logy.
26 citations
TL;DR: Although a number of reports on the cytology of Indian members have appeared, several W.Hutchinson (1959) Himalayan taxa are still unexplored and this communication presents cytological data on 17 taxa of this region.
25 citations
23 citations
22 citations
TL;DR: Cytological investigations were carried out in 18 species belonging to 13 genera and one or all the earlier chromosome reports were confirmed, finding that ploidy is equally common in the family at both the generic and specific levels.
Abstract: Cytological investigations were carried out in 18 species belonging to 13 genera. Teucrium quadrifarium (n=15) represents the first chromosome count for the species. New cytological types were observed in Ocimum canum (n=32+0-4B), O. sanctum (n=16+0-3B), Perilla ocimoides (n=14+0-2B) and in Calamintha clinopodium (n=20). For the remaining taxa, one or all the earlier chromosome reports were confirmed. Meiosis was normal in most of the taxa. The discordant chromosome numbers known in the family make it difficult to consider it as monobasic. Ocimum canum (8x) and Pogostemon plectranthoides (8x) represent the highest grade of ploidy. Intra-specific polyploidy is evident in Ocimum sanctum (2n=32, 64), O. canum (2n=24, 64, 128) and Ajuga macrosperma (2n=16, 32). Aneuploidy is equally common in the family at both the generic and specific levels.
22 citations
19 citations
TL;DR: It is suggested that centric fusions or elimination of microchromosomes, or both, are an important mechanism responsible for the karyotypic evolution of Chelonia.
Abstract: The karyotypes of three species of Chelonia of family Chelidae, from the Amazon Region of Brazil are described: Platemys platicephala, with 2n=64; Mesoclemmys gibba, whith 2n=60 and Chelus fimbriatus with 2n=50. A comparison of cyto-genetics data is made with data of other species of Chelonia. It is suggested that centric fusions or elimination of microchromosomes, or both, are an important mechanism responsible for the karyotypic evolution of Chelonia. No sex chromosome is detected in the species here studied. In male meiosis of Chelus fimbriatus, the pachytene cells showed a bivalent with a defined region lacking pairing. This defferential behavior may be taken as an indication of sexual difference.
18 citations
TL;DR: Records of chromosome number suggest that Peperomia is more primitive than Piper, and numerical and structural change in the two genera appear different, and polyploidy in the former, and structural alteration in the latter.
Abstract: From a comparison of the chromosome numbers of different species, it appears that 11 is the basic number of Peperomia and 12 of Piper. Variation in the reports of chromosome number of the same species may be due to occurrence of chromosomal biotypes.The trend of evolution in the two genera (Peperomia and Piper) appear different, numerical and structural change in the former, and polyploidy in the latter. The basic number (x=11) is represented by Peperomia argyreia, where structural alteration is clear. x×12 is represented by Pep. metallica, Pep. obtusifolia and Pep. pellucida, polyploidy occurring only in the last one.Piper cubeba (2n=24), P. magnificum (2n=24) and P. longum (2n=48), probably form a basic group of Piper. P. nigrum (2n=36, 60) is more advanced in chromosome structure. P. betle (2n=64) represents a different line having x=8 or 16.Records of chromosome number suggest that Peperomia is more primitive than Piper.
17 citations
TL;DR: Analysis of chromosome behaviour at meiosis in Crepis capillaris, 2n=2x=6+B-chromosomes, shows that the B- chromosomes influence the frequency and distri-bution of chiasmata in the A- Chromosomes.
Abstract: Analysis of chromosome behaviour at meiosis in Crepis capillaris, 2n=2x=6+B-chromosomes, shows that the B-chromosomes influence the frequency and distri-bution of chiasmata in the A-chromosomes. The mean chiasma frequency of the A's is increased by the presence of one to four B's, so too is the variance of the chiasma frequency mean between the pollen mother cells within plants. The A-chromosome bivalents differ in length, but all have similar mean chiasma frequencies, and they are all influenced to the same extent. Some data are also presented on the meiotic behaviour of the B-chromosomes themselves. Many of them get eliminated as micronuclei.
TL;DR: Morphological changes concerning floral and vegetative parts of irradiated plants mostly belonged to the primary effects of radiation and were unstable, however, change from toothed to entire margin of leaf, numerical alterations in petals and stamens, induction of narrower or twisted petals with obtuse tips, changes in the contour of androecium and intensity of colour of petals were stable.
Abstract: Irradiation of rhizomes of Nymphaea rubra by 2, 3 and 4 krad of gamma rays induced morphological and cytological changes. The 5 krad and higher doses were found to be lethal. Morphological changes concerning floral and vegetative parts of irradiated plants mostly belonged to the primary effects of radiation and were unstable. However, change from toothed to entire margin of leaf, numerical alterations in petals and stamens, induction of narrower or twisted petals with obtuse tips, changes in the contour of androecium and intensity of colour of petals were stable.Cytological alterations included formation of interchange multiples, fall in chiasma frequency and aberrations of chromosomes in the irradiated plants. Pollen fertility decreases after irradiation, and those treated with 3 and 4 krad became completely sterile.
TL;DR: The present authors have recognized a convincing difference in the karyotype of males and females of Ophisops elegans from Mosul which appears to be worth reporting.
Abstract: The karyotype of lacertid lizards is characterized by the presence of a typical number of 38 elements which can be clearly differentiated into 36 macro and a pair of micro-chromosomes (Nakamura 1931, Matthey 1931 and 1949, Arronet 1968, Kupriyanova 1968, Orlova and Orlova 1969, and Gorman 1969). Arronet (1968), while studying the karyotype of Ophisops elegans from Armenia, did not find any difference in the chromosome complements of males and females; these looked similar and showed 38 chromosomes. A similar number of chromosomes has also been described in the male of Ophisops elegans by Gorman (1969); however, he did not study the karyotype of the female. The present authors have recognized a convincing difference in the karyotype of males and females of Ophisops elegans from Mosul which appears to be worth reporting.
TL;DR: Eleven species belonging to four genera, Cyperus, Fimbristylis, Scirpus and Kobresia, have been studied and three base numbers x=8, 9 and 13 have been suggested for the genus Kob Resia.
Abstract: Eleven species belonging to four genera, Cyperus, Fimbristylis, Scirpus and Kobresia have been studied. Four species, namely, Cyperus exaltatus (n=48), C. eleusinoides (n=52), Fimbristylis tenera (n=20) and Kobresia royleana (n=40) have been worked out for the first time. New chromosome number has been recorded in Scirpus pauciflorus (n=23+0-3B). Three base numbers x=8, 9 and 13 have been suggested for the genus Kobresia.
Journal Article•
TL;DR: The karyological affinities of E. japonicum are with the subtelocentric, western North American species, rather than with those with metacentric chromosomes occurring in eastern North America.
Abstract: A number of clones of Erythronium japonicum were examined karyologically. The interphase nucleus is of the reticulate type, i.e. extremely homogeneous, with no chromocenters observed. Root tip chromosomal lengths and total genome lengths under both colchicine and 8-hydroxyquinoline pretreatments were virtually identical. All the material examined was 2n=24. Three size groups were discernible among the somatic complement, though all the chromosomes were clearly classifiable as subtelocentric. Within this asymmetrical complement, little size variation was observed in the small arms, whereas the greatest difference occurred in the long arms. Although the whole complement was subtelocentric, several of the smaller chromosomes had arm ratios close to 2:1. No nucleolar organizing chromosomes were observed for this species' complement. Based on size and centromeric position, the somatic complement can be represented as: K(2n)=24=4Lst+10Mst+10Sst. The karyological affinities of E. japonicum are with the subtelocentric, western North American species, rather than with those with metacentric chromosomes occurring in eastern North America.
TL;DR: Six taxa belonging to four species of the genus Polygonatum and one species ofThe genus Disporum have been studied cytologically and the possible mechanisms for alteration in chromosome number and karyotype have been suggested.
Abstract: Six taxa belonging to four species of the genus Polygonatum and one species of the genus Disporum have been studied cytologically. New chromosome number 2n=30 has been recorded in P. geminiflorum. In addition to the earlier reports made by Mehra and Pathania (1960), one more cytotype in P. sibiricum and three more cytotypes in P. verticillatum have been found to occur in the W. Himalayas. Disporum cantoniense with 2n=14 has been recorded from Nainital hills. The possible mechanisms for alteration in chromosome number and karyotype have been suggested.
TL;DR: This paper is a collective review of the reports previously published to corroborate the atractoplasm theory proposed by Fujii (1931) and it also offers a consolidated interpretation of the morphogenesis of mitotic spindles in eukaryota based on comparative studies on protista, metazoa and metaphyta.
Abstract: This paper is a collective review of the reports (Wada 1935-1974) previously published to corroborate the atractoplasm theory proposed by Fujii (1931) and it also offers a consolidated interpretation of the morphogenesis of mitotic spindles in eukaryota based on comparative studies on protista, metazoa and metaphyta. From the results of these investigations the author points out that the common idea of the breakdown of the nuclear membrane as one step in the spindle formation in higher plant and animal cells is a gross error. The reasons and the complications by which this error had been overlooked for nearly a century are explained and discussed from various viewpoints, such as the imperfection of observation te chniques, the nature of the research material, considerations of evolution relation ships, and gene information on the morphogenesis of mitotic spindles in eukaryota. The author makes clear that many unsolved problems and controversial interpre tations of mitosis described in current cytology books are mostly attributed to the misinterpretation of the nuclear membrane in mitosis. He has given answers to these problems. The morphological independence of mitotic spindles from the cytoplasm, and the transfiguration of metabolic nuclei into karyokinetic ones can be expressed as follows: The metabolic (resting) nucleus, spherical in form composed of 1) chromonemata, 174 B. Wada Cytologia 41 2) nucleoli, 3) nuclear sap (dispersed globular proteins), and 4) nuclear membrane. The karyokinetic nucleus (metaphase spindle), spindle-shaped in form composed of 1) chromosomes, 2) kinetochore fibers, 3) atractoplasm (arranged fibrous proteins), and 4) nuclear membrane (a strained state due to enlargement of nuclear volume in the case of higher plant and animal cells). The morphological continuity of mitotic figures and the cause and effect rela tions among them are explained in detail from prophase nucleus through metaphase spindle to the appearance of daughter nuclei in telophase, including chromosome movement in anaphase. The biological significance of the spindle-form of karyo kinetic nuclei for the mechanism of mitosis is explained.
TL;DR: The present paper deals with the fruit-bat subfamily Macroglossinae which is represented by 2 genera, Macrog Lossus and Eonycteris, in Peninsular Malaysia, which comprises two species whilst EonyCTeris is monotypic.
Abstract: The karyotypes of the insectivorous bats (Microchiroptera) are well represented (cf. Baker 1970, Capanna and Civitelli 1970, Matthey 1973, Yonenaga, Frota Pessoa and Lewis 1969). On the other hand, only seven species belonging to four genera of fruit bats (Megachiroptera) have been reported. Of the 14 species of Malayan fruit bats belonging to 11 genera (cf. Medway 1969), only 2 species be longing to a single genus Cynopterus have been studied karyologically (Yong, Dhaliwal, Lim, Teh and Start 1973). The present paper deals with the fruit-bat subfamily Macroglossinae which is represented by 2 genera, Macroglossus and Eonycteris, in Peninsular Malaysia. Macroglossus comprises two species whilst Eonycteris is monotypic. The common long-tongued fruit bat Macroglossus lagochilus Matschie is widespread in the low lands particularly in the mangroves. The hill long-tongued fruit bat Macroglossus minimus (Geoffroy) is found only in the foothills and the highlands. The cave fruit bat Eonycteris spelaea (Dobson) is widespread and locally common, particularly the caves, in the mainland.