Showing papers in "Cytologia in 1985"
TL;DR: Critical analysis of pollen mother cells of treated plants revealed chromosomal aberrations including multivalents and univalents, stickiness and despiralization at metaphase-I whereas chromatin bridges, lagging chromosomes and mis/non-orientation of chromosomes were observed at anaphase- I.
Abstract: The meiotic effects of eight organophosphorus pesticides (anthio, diazinon, dursban, ekalux, methylparathion, phendal, rogor and sumithion) were studied in barley (Hordeum vulgare L. CV. C164). Seed soak as well as spray treatments were conducted. Critical analysis of pollen mother cells (PMCs) of treated plants revealed chromosomal aberrations including multivalents and univalents, stickiness and despiralization at metaphase-I whereas chromatin bridges, lagging chromosomes and mis/non-orientation of chromosomes were observed at anaphase-I. The cyto/chromotoxic effects as observed by spraying the plants with various pesticides were same as above. However, the frequency of aberrant PMCs was comparatively less as compared to that of seed treated plants. The statistical analysis revealed that dose-response curve was linear and there existed a positive correlation between the concentration of the pesticide and the aberrations.
77 citations
TL;DR: A somatic cytological technique is described as an aid to superior resolution of primary and secondary chromosome constrictions that can accurately enable detection of 1B/1R translocation in wheat varieties, advanced lines, or hybrid progenies derived from varieties that have the1B/IR translocation.
Abstract: A somatic cytological technique is described as an aid to superior resolution of primary and secondary chromosome constrictions. Initially, intergeneric hybrids among some Triticeae can be readily identified by routine chromosome number counts, chromosome size or morphology, and satellite number. This includes those hybrids that involve parental combinations of similar polyploidy. Superior secondary constriction resolution can accurately enable detection of 1B/1R translocation in wheat varieties, advanced lines, or hybrid progenies derived from varieties that have the 1B/IR translocation. The results are discussed and photographically documented.
70 citations
TL;DR: Critical analysis of pollen mother cells of treated plants revealed chromosomal aberrations including multivalents and univalents, stickiness and despiralization at metaphase-I whereas chromatin bridges, lagging chromosomes and mis/non-orientation of chromosomes were observed at anaphase- I.
Abstract: The meiotic effects of eight organophosphorus pesticides (anthio, diazinon, dursban, ekalux, methylparathion, phendal, rogor and sumithion) were studied in barley (Hordeum vulgare L. CV. C164). Seed soak as well as spray treatments were conducted. Critical analysis of pollen mother cells (PMCs) of treated plants revealed chromosomal aberrations including multivalents and univalents, stickiness and despiralization at metaphase-I whereas chromatin bridges, lagging chromosomes and mis/non-orientation of chromosomes were observed at anaphase-I. The cyto/chromotoxic effects as observed by spraying the plants with various pesticides were same as above. However, the frequency of aberrant PMCs was comparatively less as compared to that of seed treated plants. The statistical analysis revealed that dose-response curve was linear and there existed a positive correlation between the concentration of the pesticide and the aberrations.
66 citations
TL;DR: Karyotype analyses were made using root tip mitosis in 21 species of South Indian Apiaceae as mentioned in this paper, and the first record of chromosome numbers have been made in Hydro-cotyle conferta (2n=18), H. candolleana (2 n=18).
Abstract: Karyotype analyses were made using root tip mitosis in 21 species of South Indian Apiaceae. First record of chromosome numbers have been made in Hydro-cotyle conferta (2n=18), H. rotundifolio (2n=18), Pimpinnella pulneyensis (2n=18), P. candolleana (2n=18), Heracleum rigens (2n=40), H. ceylanicum (2n=44), H. sprengelianum (2n=14), H. courtallense (2n=40) H. hookerianum (2n=46), H. aquilegifolium (2n=46), H. candolleanum (2n=40) and H. pedatum (2n=46). The most commonly occurring somatic chromosome number is 2n=18 and 2n=22. It is evident from the present investigation and those data available from earlier studies in this family that aneuploidy and euploidy together with karyotypic asym-metry of chromosomes play important role in the origin and evolution of the species studied.
39 citations
30 citations
TL;DR: To determine whether RNA synthesis occurs in trinucleate pollen, Secale cereale pollen was studied and the vegetative and sperm cell nuclei of the in vitro grown pollen tubes were shown by autoradiography to incorporate [5-3H] uridine, interpreted as indicating the synthesis of RNA.
Abstract: In binucleate pollen tubes the vegetative and generative cell nuclei are known to synthesize RNA. Nothing is known about RNA synthesis in trinucleate pollens. To determine whether RNA synthesis occurs in trinucleate pollen, Secale cereale pollen was studied. The vegetative and sperm cell nuclei of the in vitro grown pollen tubes were shown by autoradiography to incorporate [5-3H] uridine. This incorporation was interpreted as indicating the synthesis of RNA.
29 citations
TL;DR: Various membranous configurations produced by the host and fungus have been studied in five different vesicular-arbuscular (VA) mycorrhizae using electron microscope techniques and the structural, cytochemical and enzymological aspects of these membrane formations show that they areproduced by the plasmalemma and correspond to plas malemmasomes.
Abstract: Various membranous configurations (vesicles, tubules, membrane layers) produced by the host and fungus have been studied in five different vesicular-arbuscular (VA) mycorrhizae using electron microscope techniques. The structural, cytochemical and enzymological aspects of these membrane formations show that they are produced by the plasmalemma and correspond to plasmalemmasomes. The plasmalemmasomes in the VA fungal hyphae appear to originate by invagination of the fungal plasmalemma whilst those of the host cell form by extrusion of the host membrane into the interfacial matrix. The presence of plasmalemmasomes in one of the mycorrhizal symbionts does not necessarily correspond to their presence in the other. (The possible role of these plasmalemma formations in VA mycorrhizal associations is discussed).Plusieurs configurations membranaires (vesicules, tubules, systemes membranaires concentriques) produites par I'hote et le champignon ont ete etudiees en microscopie electronique chez cinq associations mycorhiziennes vesiculo-arbusculaires (VA) differentes. Les aspects structuraux, cytochimiques et enzymologiques de ces formations membranaires montrent qu'elles sont produites par le plasmalemme et qu'elles correspondent aux plasmalemmasomes.Les plasmalemmasomes dans les hyphes du champignon VA paraissent prendre naissance de l'invagination du plasmalemme fongique tandis que ceux de la cellule-hote se forment par evagination de la membrane de l'hote dans la matrice de l'interface. Toutefois, on ne trouve pas necessairement ces formations simultanement dans les deux symbiotes. Le role eventuel de ces structures plasmalemmiques dans les associations mycorhiziennes est discute.
19 citations
TL;DR: Fifteen species of Ranunculaceae under eight genera have been studied, mostly collected from different regions of Ooty and Kodaikanal of Western Ghats, and a wide range of chromosome numbers, chromosome sizes and total chromosome lengths of various species studied is shown.
Abstract: Fifteen species of Ranunculaceae under eight genera have been studied, mostly collected from different regions of Ooty and Kodaikanal of Western Ghats. First record of chromosome numbers has been made in Ranunculus wallichianus, R. subpinnatus, R. reniformis, Clematis wightianus, Thalictrum dalzellii and T. saniculaeforme. On the basis of previous and present cytological data, there are n=7 and n=8 series in Ranunculus. All the species of Ranunculus studied here are higher polyploids and both aneuploidy and euploidy play important role in speciation.The previous karyological analyses of Anemone reveal two distinct series, one with n=8 and the other n=7. Both A. rivalaris and A. japonica have 2n=24 chromosomes and they should have derived from n=8 series. Both in the larger size and the same number of chromosomes, Naravelia zeylanica and Clematis wightianus are related together.The presence of fewer number of chromosomes and larger size of them indicates that Nigella damascena is a primitive species. All the three species of Thalictrum, namely T. javanicum, T. dalzellii and T. saniculaeforme possess 2n=16 chromosomes and perhaps, these taxa are diploids derived from n=8 series. The chromosomes are comparatively smaller in size in all these species.Aquilegia canadensis has 2n=32 chromosomes. This may be a polyploid and it should have originated from n=8 basic chromosome series.The population of Delphinium ajacis studied here is a diploid and that of D. belladonna a triploid and the basic chromosome number in Delphinium may be n=8. As far as this genus is concerned, higher polyploidy plays important role in specification.In general, the taxa of Ranunculaceae studied show a wide range of chromo-some numbers from 2n=12 to 2n=46. As most of the taxa studied show either 2n=16 or multiples of n=8, the basic number of the family may be n=8 and the other basic numbers should have derived from it. The species are highly variable and polyphyletic in nature, as evidenced by the wide range of chromosome numbers, chromosome sizes and total chromosome lengths of various species studied.
19 citations
TL;DR: Two organic and inorganic fungicides tested proved to be potential for causing genetic hazards in the biological system thereby justifying their banning in agriculture.
Abstract: Two organic (ethyl mercuric chloride and mixture of ethyl mercuric chloride and phenyl mercuric acetate) and an inorganic (mercuric chloride) fungicides were tested on Allium cepa root tips. Different chromosomal aberrations were noted. Chromatid exchanges, breaks, ring chromosomes etc. showed strong mutagenic potentialities of these chemicals. Presence of polyploid cells indicated the role of fungicides in inhibiting spindle system. Binucleate cells appeared in low concentrations after long period of treatment indicating the action of the chemicals on the membrane system. These chemicals proved to be potential for causing genetic hazards in the biological system thereby justifying their banning in agriculture.
19 citations
TL;DR: The insecticide showed no significant effect on the mitotic index, meanwhile it induced a highly significant percentage of cells with chromosome aberrations after both seed-soak- and root-treatments.
Abstract: The effect of the insecticide O, S-dimethyl phosphoramidothioate (Methamidophos) has been studied on root-mitosis of Vicia faba. Two types of treatments were conducted: seed-soak-treatment for 24 hours and root-treatment for 4 hours. Different concentrations of the insecticide ranging from 500 ppm to 31.25 ppm have been used in each treatment.The insecticide showed no significant effect on the mitotic index, meanwhile it induced a highly significant percentage of cells with chromosome aberrations after both seed-soak- and root-treatments. Roots treated with 500 ppm of Methamidophos recovered after replacement in water for 48 hours.Disturbed meta- and anaphases where the chromosomes spread irregularly over the cell dominated. Other abnormalities e.g. chromosome stickiness, lagging chromosomes and chromosome fragmentation were observed.
18 citations
TL;DR: Seed germinability, survival rates, LD50, the M1 variants, the total mutation frequency including chlorophyll mutations, viable mutations and non-viable morphological mutations have been enumerated and mode of inheritance of some of the mutant traits was studied.
Abstract: For induction of mutations, seeds (1.5% moisture content) of Nigella sativa L. (black cummin) were treated with 4. 6, 8, 10, 20 and 30 KR of X-rays and 0.5%, 0.75% and 1.0% EMS for 2 and 4 hours. Seed germinability, survival rates, LD50, the M1 variants, the total mutation frequency including chlorophyll mutations, viable mutations and non-viable morphological mutations have been enumerated. Mutagenic efficiency and effectiveness were determined. Mode of inheritance of some of the mutant traits was also studied.
TL;DR: Chromosome analysis of seven species of Asparagus and four populations of A. racemosus has revealed that both polyploidy (20, 40, 60) and structural alterations have played a role in speciation of AsParagus associated with variation in sapogenin content.
Abstract: Chromosome analysis of seven species of Asparagus and four populations of A. racemosus has revealed that both polyploidy (20, 40, 60) and structural alterations have played a role in speciation of Asparagus associated with variation in sapogenin content.
TL;DR: There are histochemical indications that the middle midgut, and especially its posterior region, can be a differentiated area of sugar storage.
Abstract: The posterior midgut of Drosophila auraria larvae, and more specifically its anterior half, must be considered an important region for the digestion and the uptake of nutrients. The cells, and the region of the central lumen they define, are unique in that they give positive reaction for alkaline phosphatase; they also give the strongest histochemical reaction for leucine aminopeptidase. There are histochemical indications that the middle midgut, and especially its posterior region, can be a differentiated area of sugar storage.
TL;DR: Karyotypes of three cultivars of Lactuca sativa, Lactuba serriola and a cultivar of Cichorium intybus were analysed in detail so that essential comparative information was available for use in later studies.
Abstract: Karyotypes of three cultivars of Lactuca sativa (Webb's Wonderful, Lobjoit's Green Cos and Tom Thumb), Lactuca serriola collected from the field in the county of Essex, U.K. and a cultivar of Cichorium intybus (Witloof Chicory), were analysed in detail so that essential comparative information was available for use in later studies (Haque and Godward, Papers II, III and IV). Statistical data on chromosome lengths and centromere positions, together with the recognition of the nucleolar-organising chromosomes, enabled the nine chromosomes of the haploid sets to be recognised individually, and these were designated A, B, C, D, E, F, G, H and I, C and E being the nucleolar organising chromosomes, these being recognised in C. intybus for the first time. There were slight differences in chromosome lengths, the Lactuca sativa cultivars and L. serriola being distinguishable by their mean lengths, but only those of C. intybus were significantly smaller. Comparisons with the previously published data on Lactuca and Cichorium are made.
TL;DR: In this article, the karyotypes of four Iberian Cyprinids taxa were established by the analysis of the respective kidney metaphasic plates, and the endemisms of uniseriated pharyngeal teeth were characterized by presenting the most common diploid number found in the known Cyphinidae (2n=50).
Abstract: The karyotypes of four Iberian Cyprinids taxa are established by the analysis of the respective kidney metaphasic plates.Such endemisms of uniseriated pharyngeal teeth are characterized by presenting the most common diploid number found in the known Cyprinidae (2n=50). Their chromosomic complements are asymmetric and possess a reduced group of acrocentric pairs so, a high fundamental arm number. There is no evidence neither of heterochromosomes nor of intra and/or interindividual polymorphisms, with the exception of Ch. lemmingi in what concerns the later case.Morphometric data regarding the six more conspicuous chromosomes pairs are presented for the studied species, and their relationships comparatively discussed according to the resolution obtained.
TL;DR: It is concluded that waste waters of industrial origin not only upset the balance in aquatic ecosystem but also considerable genetic impact on plants.
Abstract: Cytological effects of dyes manufacturing industry waste water on root meristematic cells of Allium cepa were investigated. The results obtained showed that the effluents induce various types of abnormalities such as chromosome breaks, C-mitosis, binucleate cells, tri- and terta-polar cells, nuclear cleavage, etc. It is concluded that waste waters of industrial origin not only upset the balance in aquatic ecosystem but also considerable genetic impact on plants.
TL;DR: Evidence taken in conjunction with the data obtained from anatomy, morphology, palynology, embryology and floral biology, support the separation of the two genera Peperomia and Piper into two different families under Piperales as Peperomiaceae and Piperaceae, as done by certain taxonomists.
Abstract: Fifty three taxa have been studied during the present investigation, including eight species of Piper and nine of Peperomia. In Piper chromosome numbers ranging from 2n=24 to 195 have been found and polyploidy has been shown to be an important factor in evolution. The species of Piper studied here have multiples of 13, except P. cubeba L.f. which is deep-seated for the genus. However in P. cubeba L.f. n=12 chromosomes may represent the basic set from which n=13 might have been derived and this number became deep-seated in the species of Piper, possibly due to selective advantage. All the species of Piper except P. cubeba L.f. show a gross uniformity in the karyotype. However, differences in the number of nucleolar chromosomes have been recorded.In Peperomia, eight taxa have shown 2n=22 chromosomes, whereas in P. nummularifolia H.B.K. and P. pellucida H.B.K. 2n=23 and 2n=44 chromosomes are seen respectively. In the genus Peperomia the basic set of n=11 chromosomes is pronounced. The karyotype is characterised by relatively larger chromosomes than that of the genus Piper. The species of Peperomia differ in minute details of karyotype, suggesting the role of minute structural alterations in evolution.Cytologically the two genera Peperomia and Piper are quite distinct from each other. These evidences taken in conjunction with the data obtained from anatomy, morphology, palynology, embryology and floral biology, support the separation of the two genera into two different families under Piperales as Peperomiaceae and Piperaceae, as done by certain taxonomists, with Peperomia repre-senting a primitive state in evolution.
TL;DR: Differentiation of the Ubisch bodies and their lytic activity are simultaneously accompanied by intensive vacuolation of the tapetal cells, indicating relations of these two accurately programed processes.
Abstract: Ubisch bodies observed on the surface of tapetal cells in the anthers of Lilium henryi, are composed by the central electron-transparent part (core or nucleus) and by the marginal electron-dense zone. The central part is connected by a canal with the plasma membrane of the tapetal cells. ER participates at Ubisch bodies formation, it gathers electron-dense material, which causes their dilatation. During the formation of the electron-transparent nucleus of the Ubisch body, it is possible to observe a membrane on the surface of it. Clusters of dense material are apposed gradually on the surface of the nucleus, forming the dark marginal zone of the body. The Ubisch bodies are transported to the surface of the tapetal cells by the canals, they are connected with the plasma membrane and become lytically active. At the contact of the Ubisch bodies with the plasma membrane, lysis occurs of the surface parts of the cells. Basing on these observations, we consider Ubisch bodies to be a part of the lytic compartment of the tapetal cells. Differentiation of the Ubisch bodies and their lytic activity are simultaneously accompanied by intensive vacuolation of the tapetal cells, indicating relations of these two accurately programed processes.
TL;DR: A correlation of ploidy with general geographical distribution shows that the species native to Cape Winter-Rainfall region are diploid and those occurring in Summer- Rainfall region and Tropical Africa range from diploids to hexaploid; while Mediterranean, European and West Asian species are all polyploid, ranging from tetraploid to dodecaploid.
Abstract: Based on x=15, the species in the genus depict a range of ploidy from diploid (2n=30) to dodecaploid (2n=180), whereas all the garden coultivars studied are tetraploid (2n=60). The two diploid taxa G. tristis L. and Acidanthera bicolor Hochst. show regular meiosis with 15 bivalents and near normal pollen stainability. Among tetraploid (2n=60) taxa, G. italicus Mill. is characterised by regular occurrence of 30 bivalents leading to normal anaphase segregation and 91.6 per cent pollen stainability. The garden cultivars, however, show at metaphase I predominant bivalent formation with some quadrivalents, trivalents and univalents. While normal anaphase I segregation (30:30) was observed in most of the cells, unequal segregation also resulted due to trivalents and univalents. Pollen stainability ranges from 49.8 to 98.6 per cent. The pentaploid taxa comprising of six cultivated types of G. psittacinus hybr. also exhibited predominant bivalent formation along with pentavalents, quadrivalents, trivalents and univalents. Anaphase I is irregular due to unequal disjunction of trivalents and univalents. Pollen stainability ranges from 65.07 to 94.2 per cent. G. communis (2n=176) is characterized by trivalents, bivalents and univalents. Bivalent formation is unexpectedly high with a mean of 84.75 per cell and full complement of 88 bivalents was observed in 20 per cent of the cells studied. Pollen stainability is 87.16 per cent.A correlation of ploidy with general geographical distribution shows that the species native to Cape Winter-Rainfall region are diploid and those occurring in Summer-Rainfall region and Tropical Africa range from diploid to hexaploid; while Mediterranean, European and West Asian species are all polyploid, ranging from tetraploid to dodecaploid.
TL;DR: It is conceivable that the red spherical bodies appearing in the seedling hypocotyls of a radish cultivar has some special properties of cytoplasm.
Abstract: Microchemical and cytochemical tests were conducted on the red spherical bodies appearing in the seedling hypocotyls of a radish cultivar (Rhaphanus sativus L.), “Kohaku”.In the fresh material of the hypocotyls the red body was broken down by the treatments with weak acids and alkalines, and also showed negative color change with Fehling's reaction and iodine-potassium iodine reaction.In the paraffin sections clear stainings of the spherical bodies were obtained from the following dyes: safranin, both of basic and acidic fuchsins, fast green, methyl blue, orange G and aceto-carmine. However, negative results were given with methylene blue in both of alcohol and water, ruthenium red, sudan III, toluidine blue and nile blue.From these results it is conceivable that the spherical body has some special properties of cytoplasm.The relationship between the appearance of the body and the formation of anthocyanin was discussed.
TL;DR: The histochemical constitution and relationship between the sporogenous tissue and tapetum in the anther of Euphorbia pulcherrima Wilid is studied and the differentiation and chemical nature of orbicular bodies based on azure B stain in thetapetum is given.
Abstract: The histochemical constitution and relationship between the sporogenous tissue and tapetum in the anther of Euphorbia pulcherrima Wilid. is studied. The substances localized are insoluble carbohydrates, RNA and proteins. The sporogenous tissue until it differentiates into PMCs, stores abundant PAS positive grains. This is a distinctive and a rare feature. RNA and proteins are also high in it. In PMCs all these substances reduce to low level in the cytoplasm. From microspore stage to mature pollen consistent increase in RNA and proteins is seen. But the PAS positive grains are noticed only for a short period in the freed spores and they are again accumulate when pollen matures. The differentiation and chemical nature of orbicular bodies based on azure B stain in the tapetum is given.Orbicules from the beginning to end exhibit green colour. Therefore, they are These chemically similar to pollen wall. Extensive deposition of PAS positive callose thickening around the PMCs and its persistence until meiosis is noticed. The probable implications of all these events are discussed in relation of male gametophyte development.
TL;DR: The identity of the so-called cresecent cell in the hemolymph of the cockroach, Gromphadorhina portentosa (Schaum) (Dictyoptera: Blaberidae) has been established and these hemocytes are indeed oenocytoids (OEs).
Abstract: The identity of the so-called cresecent cell in the hemolymph of the cockroach, Gromphadorhina portentosa (Schaum) (Dictyoptera: Blaberidae) has been established. These hemocytes are indeed oenocytoids (OEs). The identity of these cells was con-firmed by observations in both the last instar nymphs and adults. The OEs appear as polymorphic anucleate cells. Each OE has a crescent-shaped inclusion body that generally fills the cell and gradually diminishes in size and density as the cell ages. The OEs vary from 16 to 28μm in length and 10 to 22.4μm in width. They generally constitute 2% of the total hemocyte counts in both nymphs and adults. The most peculiar features of the OEs in this cockroach are presence of a single crescent-shaped cytoplasmic body and gradual nuclear extrusion as these cells age. No nuclear extrusion was observed in any of the other five types of hemocytes found in this cockroach. The nuclear extrusion may occur at any point along the length of the cell, thus producing the various forms of anucleate cells. Histochemically, the inclusion body shows intense PAS-positivity and is Sudan Black B-negative. These cells may nlav an indirect role in the final stages of cuticle formation.
TL;DR: Interspecific as also intergeneric hybrids within occidental genera of Maydeae have been suc cessfully obtained and they have been studied cytologically suggesting the inter relationships and the origin of cultivated maize and its genome from among its available ancestors.
Abstract: presented in India by three species viz., C. aquatica Roxb. (2n=10), C. lacryma-jobi L. (2n=20) and C. gigantea Koen. ex Roxb. (2n=20 and 2n=40). Interspecific as also intergeneric hybrids within occidental genera of Maydeae have been suc cessfully obtained and they have been studied cytologically suggesting the inter relationships and the origin of cultivated maize and its genome from among its available ancestors (Longley 1937, Mangelsdorf and Reeves 1939, Randolph 1950, 1955, Farquharson 1957, Singh and Paliwal 1960, Koul and Paliwal 1961). Man
TL;DR: The division of mitochnodrial nuclei in Amoeba proteus, Paramecium caudatum, Nitella flexilis and Allium cepa was investigated using 4-diamidino-2-phenylindole epifluorescent microscopy and mitochondrial DNA probably duplicated and divided equally into daughter mitochondria.
Abstract: The division of mitochnodrial nuclei in Amoeba proteus, Paramecium caudatum, Nitella flexilis and Allium cepa was investigated using 4'-6-diamidino-2-phenylindole (DAPI) epifluorescent microscopy. The mitochondria each contained one mt-nucleus in Amoeba proteus and Paramecium caudatum and one or two mt-nuclei in Nitella flexilis and Allium cepa. The ratio of fluorescent intensity (grain density of negative film) among one DNA molecule of a T4 phage particle and mt-nuclei of spherical mitochondria in Physarum polycepaalum, Amoeba proteus, Paramecium caudatum, Nitella flexilis and Allium cepa was about 1:16:22:5:0.4:0.4. That is, the mitochondrial DNA content in Nitella flexilis and Allium cepa was much smaller than those in Amoeba proteus and Paramecium caudatum. The mitochondria and their nuclei in Amoeba proteus and Paramecium caudatum as well as Physarum polycephalum divided simultaneously by constriction, while segregation of mitochondria) nuclei occurred before the mitochondrial division in Nitella flexilis and Allium cepa. The fluorescent intensity of mt-nuclei in dumbbell-shaped mitochondria of Paramecium caudatum and Allium cepa was about twice that in spherical mitochondria. Therefore, mitochondrial DNA probably duplicated and divided equally into daughter mitochondria.
TL;DR: The karyotype of Paraechinus aethiopicus consists of 48 chromosomes comprising 14 pairs of metacentric, 9 pairs of submetacentric and a pair of meticentric sex chromosomes, X and Y.
Abstract: The karyotype of Paraechinus aethiopicus consists of 48 chromosomes comprising 14 pairs of metacentric, 9 pairs of submetacentric and a pair of metacentric sex chromosomes, X and Y. The fundamental number is 96 and the fundamental number of autosmes is 92. Secondary constrictions and subtelocentric chromosomes are not seen in this animal.
TL;DR: A busyy mutant with desynaptic behaviour of chromosomes has been recovered from the M2 population of Nigella sativa L. (black cummin) following 2 hours treatment with 0.5% EMS and possibly, the mutant gene has shown pleiotropic effect or the traits were closely linked with the bushy phenotype.
Abstract: A busyy mutant with desynaptic behaviour of chromosomes has been recovered from the M2 population of Nigella sativa L. (black cummin) following 2 hours treatment with 0.5% EMS. A single pair of recessive genes (bu/bu) has been ascribed for bushyness and the mutant bred true in the subsequent generations. The bushy mutant plant could always be characterized by their delayed germination, flowering and maturity, high frequency of sterile pollen, poor seed setting and desynaptic behaviour of chromosomes. Possibly, the mutant gene has shown pleiotropic effect or the traits were closely linked with the bushy phenotype.
TL;DR: The karyotype analyses show that both genera are characterised by the presence of mostly submetacentric and telocentric chromosomes showing thereby that the two generas are highly evolved but in different lines, eventhough, they might have been originated from a common ancestor.
Abstract: Cytotaxonomical investigation has been made in 21 species of Piper and Peperomia, of which first records of chromosome numbers have been made in Piper attenuatum, P. galeatum, P. schmidtii, P. wightii, P. brachystachum, P. hookeri, Peperomia marmorata and P. rubella.11 is the basic number for Peperomia and 12 for Piper as evidenced by the present investigations. The species of Piper are higher polyploids and aneuploids and the species of Peperomia are mostly aneuploids. The karyotype analyses show that both genera are characterised by the presence of mostly submetacentric and telocentric chromosomes showing thereby that the two genera are highly evolved but in different lines, eventhough, they might have been originated from a common ancestor.
TL;DR: It is evident that numerical and gross structural changes in chromosomes have not played any maior role in si eciation and evolution of the genus.
Abstract: Detailed karyomorphology of four species of Zingiber from South India, has been studied, namely Z. officinale (2n=22), Z. zerumbet (2n=22), Z. wightianum (2n=22) and Z. macrostachyum (2n=22). Karyomorphological data indicate that except Z. officinale, where it is relatively symmetrical (1A), all the other three species are moderately asymmetrical (2A).Chromosomal evolution on the genus is discussed in the light of available cytological findings. The data show that this is a monobasic genus with x=11. Although the karyotypes of the four species showed general uniformity, in final details recognisable differences were noticed with regard to distribution of secondary constrictions and centromere positions of a few individual chromosomes. It is evident that numerical and gross structural changes in chromosomes have not played any maior role in si eciation and evolution of the genus.
TL;DR: The presence of these enzymatic activities in the interface strengthen the hypothesis of a mutualistic symbiosis during the biotrophic phase.
Abstract: En localisant, au niveau ultrastructural, les activites ATPasiques et NDPasiques, les auteurs se proposent d'etudier les rapports entre les deux partenaires de la symbiose pendant la phase biotrophique.Les activites ATPasiques du plasmalemme de l'hote et du plasmalemme de l'endophyte montrent l'existence de transports actifs au niveau de l'interface. Les activites NDPasiques sont souvent observees sur les sites d'edification de materiel parietal. Celles mises en evidence dans la matrice et sur le plasmalemme de l'hote correspondent a la mise en place, par l'hote de la couche d'isolement.Les activites NDPasiques du plasmalemme de l'endophyte pourraient etre impliquees dans les transports entre la cellule-hoote et l'endophyte.La presence de ces activites enzymatiques dans l'interface confirme l'hypothese de relations mutualistes pendant la phase biotrophique.A cytochemical study was made to examine the possibility that ATPase-activities and NDPase-activities may be involved in the transfer of nutrients between the Orchid and the fungus during the biotrophic phase of the symbiosis.The ATPase-activities of the fungal plasmalemma and the host plasmalemma show that the interface is a site of active transfer processes.The NDPase-activities are often associated with the building of cell wall.The activities of the matrix and the host plasmalemma are involved in the deposition of the encasement material laid down by the host.The activity of the endophyte plasmalemma may be involved in transport between the host cell and the symbiont.The presence of these enzymatic activities in the interface strengthen the hypothesis of a mutualistic symbiosis during the biotrophic phase.