Consulta: subjectFacets:"Meiosis"
Registros recuperados: 57
Data/hora: 16/06/2024 03:28:25

Backcrossing to increase meiotic stability in triticale.
Provedor de dados: 119
Autores: GIACOMIN, R. M.; ASSIS, R.; BRAMMER, S. P.; NASCIMENTO JUNIOR, A. do; SILVA, P. R. da.
Tipo: Separatas
Palavras-chave: X Triticosecale; Wittmack; Pollen viability; Cytogenetic.; Triticale.; Meiosis; Plant breeding.
Ano: 2015
URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1029920

Microsporogenesis in Paspalum conspersum Schrad. (Virgata group) with different ploidy levels.
Provedor de dados: 119
Autores: JANKE, L.; SOUZA, F. H. D. de; VALLS, J. F. M.; PAGLIARINI, M. S.
Tipo: Separatas
Palavras-chave: 2n gamete.; Paspalum; Poaceae; Interspecific hybridization; Meiosis; Pentaploidy.
Ano: 2013
URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1040052

Complete asynapsis resulting in 2n pollen formation in Paspalum jesuiticum Parodi (Poaceae).
Provedor de dados: 119
Autores: BERNARDO FILHO, R. A.; SANTOS, A. C. C.; SOUZA, F. H. D. de; VALLS, J. F. M.; PAGLIARINI, M. S.
Tipo: Separatas
Palavras-chave: Poaceae; Hexaploidy; Interspecific hybridization; Meiosis; Polyploidy.
Ano: 2014
URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/983777

Microsporogenesis in Brachiaria bovonei (Chiov.) Robyns and B. subulifolia (Mez) Clayton (Poaceae).
Provedor de dados: 119
Autores: RISSO-PASCOTTO, C.; PAGLIARINI, M. S.; VALLE, C. B. do.
ABSTRACT - Some African species of Brachiaria have been introduced into the Americas and became the most important forage for pastures in the tropics. New cultivars can be obtained either from direct selections from the natural existing variability in the germplasm collections or from interspecific hybridizations. Polyploidy is predominant in the genus Brachiaria and correlated with apomixis which complicates hybridization. The objective of cytological studies underway on the Brachiaria germplasm collection at Embrapa Beef Cattle is to determine the chromosome number and meiotic behavior of accessions. For the breeding of Brachiaria species, compatible sexual and apomictic accessions need to be identified. Microsporogenesis was evaluated in two accessions...
Tipo: Artigo de periódico
Palavras-chave: Braquiária; Brachiaria bovonei; Brachiaria; Gramínea Forrageira; Meiose; Melhoramento Genético Vegetal; Pastagem; Poliploidia; Cultivars; Meiosis; Microsporogenesis; Chromosome number; Polyploidy.
Ano: 2009
URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/573293

Meiotic behavior of interspecific hybrids between artificially tetraploidized sexual Brachiaria ruziziensis and tetraploid apomictic B. brizantha (Poaceae).
Provedor de dados: 119
Autores: FELISMINO, M. F.; PAGLIARINI, M. S.; VALLE, C. B. do.
ABSTRACT -The meiotic behavior of four interspecific promising hybrids was evaluated by conventional cytological methods. The female genitors were two artificially tetraploidized sexual accessions of B. ruziziensis (R41 and R44, 2n = 4 ? = 36), which were crossed to an agronomically superior natural tetraploid apomictic genotype of B. brizantha (B140 - BRA003395). Three of them (HBGC313, HBGC 315, and HBGC324) were sexual and one (HBGC325) apomictic. Analyses of some cells in diakinesis revealed multivalent chromosome configurations, suggesting that genetic recombination and introgression of some genes could be present. The four hybrids had different types of meiotic abnormalities at various frequencies. Abnormalities related to irregular chromosome...
Tipo: Artigo de periódico
Palavras-chave: Brachiaria Brizantha; Brachiaria Ruziziensis; Citogenética Vegetal; Melhoramento Genético Vegetal; Pastagem; Planta Forrageira; Cytogenetics; Forage grasses; Meiosis; Plant breeding.
Ano: 2010
URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/855809

New cytogenetic data for three species of Pentatomidae (Heteroptera): Dichelops melacanthus (Dallas, 1851), Loxa viridis (Palisot de Beauvois, 1805), and Edessa collaris (Dallas, 1851).
Provedor de dados: 119
Autores: DIONISIO, J. F.; BALDISSERA, J. N. da C.; TIEPO, A. N.; FERNANDES, J. A. M.; SÓSA-GOMEZ, D. R.; ROSA, R. da.
Tipo: Artigo de periódico
Palavras-chave: Meiose; Percevejo; Heterochromatin; Meiosis; Pentatomidae.
Ano: 2020
URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1129064

Microsporogenesis analysis validates the use of artificially tetraploidized Brachiaria ruziziensis in breeding programs.
Provedor de dados: 119
Autores: PAULA, C. M. P.; FIGUEIREDO, K. G.; SOUZA SOBRINHO, F. de; BENITES, F. R. G.; DAVIDE, L. C.; TECHIO, V. H.
Tipo: Separatas
Palavras-chave: Pollen grain.; Breeding; Forage; Meiosis; Polyploidy.
Ano: 2016
URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1056860

Evidence of sexuality in induced tetraploids of Brachiaria brizantha (Poaceae).
Provedor de dados: 119
Autores: ARAÚJO, A. C. G.; NÓBREGA, J. M.; POZZOBON, M. T.; CARNEIRO, V. T. de C.
Tipo: Separatas
Palavras-chave: Caryopses; Cromossomo; Apomixia; Embryo sac; Meiosis; Ploidy.
Ano: 2005
URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/186689

Evidence of programmed cell death during microsporogenesis in an interspecific Brachiaria (Poaceae: Panicoideae: Paniceae) hybrid.
Provedor de dados: 119
Autores: FUZINATTO, V. A.; PAGLIARINI, M. S.; VALLE, C. B. do.
Morphological changes have been investigated during plant programmed cell death (PCD) in the last few years due to the new interest in a possible apoptotic-like phenomenon existing in plants. Although PCD has been reported in several tissues and specialized cells in plants, there have been few reports of its occurrence during microsporogenesis. The present study reports a typical process of PCD during meiosis in an interspecific Brachiaria hybrid leading to male sterility. In this hybrid, some inflorescences initiated meiosis but it was arrested in zygotene/pachytene. From this stage, meiocytes underwent a severe alteration in shape showing substantial membrane blebbing; the cytoplasm became denser at the periphery; the cell nucleus entered a progressive...
Tipo: Artigo de periódico
Palavras-chave: Braquiária; PCD; Campo Grande; Mato Grosso do Sul; Brasil; Feed crops; Feed grasses.; Melhoramento genético vegetal; Citogenética vegetal; Planta Forrageira; Gramínea forrageira; Hibrido; Meiose.; Cytogenetics; Plant breeding; Hybrids; Meiosis; Brazil.
Ano: 2007
URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/326640

Complete asynapsis resulting in 2n pollen formation in Paspalum jesuiticum Parodi (Poaceae).
Provedor de dados: 119
Autores: BERNARDO FILHO, R. A.; SANTOS, A. C. C.; SOUZA, F. H. D. de; VALLS, J. F. M.; PAGLIARINI, M. S.
Tipo: Separatas
Palavras-chave: Poaceae; Hexaploidy; Interspecific hybridization; Meiosis; Polyploidy.
Ano: 2014
URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/994921

Implications of mitotic and meiotic irregularities in common beans (Phaseolus vulgaris L.).
Provedor de dados: 119
Autores: LIMA, D. C.; BRAZ, G. T.; REIS, G. B. dos; TECHIO, V. H.; DAVIDE, L. C.; ABREU, A. de F. B.
The common bean has great social and economic importance in Brazil and is the subject of a high number of publications, especially in the fields of genetics and breeding. Breeding programs aim to increase grain yield; however, mitosis and meiosis represent under explored research areas that have a direct impact on grain yield. Therefore, the study of cell division could be another tool available to bean geneticists and breeders. The aim of this study was to investigate irregularities occurring during the cell cycle and meiosis in common bean. The common bean cultivar used was BRSMG Talismã, which owing to its high yield and grain quality is recommended for cultivation in Brazil. We classified the interphase nuclei, estimated the mitotic and meiotic index,...
Tipo: Artigo de periódico
Palavras-chave: Feijão; Phaseolus Vulgaris; Melhoramento Genético Vegetal; Pólen; Beans; Meiosis; Plant breeding; Mitosis; Pollen.
Ano: 2016
URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1122251

Meiotic behavior in full and half-stb hybrids between Brachiaria ruziziensis and B. brizantha (Poaceae).
Provedor de dados: 119
Autores: FELISMINO, M. F.; PAGLIARINI, M. S.; VALLE, C. B. do.
Tipo: Parte de livro
Palavras-chave: Braquiária.; Brachiaria Ruziziensis; Brachiaria Brizantha; Citogenética Vegetal; Hibrido; Melhoramento Genético Vegetal.; Meiose; Cytogenetics; Hybrids; Plant breeding.; Meiosis.
Ano: 2007
URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/326272

Comportamiento meiótico de diferentes especies de lulo, Solanum sp
Provedor de dados: 109
Autores: Pareja Ordóñez,Nancy Maricela; Santacruz Ordóñez,Nazira Katherine; Ordóñez Jurado,Héctor Ramiro; Lagos Burbano,Tulio César.
Se realizó un análisis del comportamiento meiótico de las especies de lulo S. hirtum, S. quitoense y S. sessiliflorum, siguiendo la metodología convencional para los estudios de microsporogénesis. Se tomaron botones florales en diferentes estados de desarrollo, fijándolos por 24 horas en una solución de tres partes de etanol por una parte de ácido acético, saturada con trazas de cristales de cloruro férrico. Para la preparación de las placas se siguió la técnica de aplastamiento, se liberaron las células madres del grano de polen y finalmente se hicieron las observaciones bajo microscopía de luz. El análisis mostró que la meiosis se presenta en longitudes de antera que van desde los 2,79 mm hasta los 4,45 mm. La normalidad meiótica fue del 100%, tanto para...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Meiosis; Variabilidad; Microsporogénesis; Índice meiótico; Normalidad meiótica.
Ano: 2010
URL: http://www.scielo.org.co/scielo.php?script=sci_arttext&pid=S0120-28122010000400002

LA COMPETENCIA DEL OVOCITO: QUÉ, CÓMO Y CUÁNDO
Provedor de dados: 37
Autores: TARAZONA¹,ARIEL; LÓPEZ,ANGELA; OLIVERA-ANGEL,MARTHA.
La producción de embriones in vitro ha sido una herramienta útil para el desarrollo de técnicas como la clonación y la transgénesis, que han revolucionado los campos de la ciencia y la tecnología. La técnica básica para la maduración, fertilización y cultivo in vitro de los embriones produce, desde sus inicios, bajas tasas de desarrollo hasta el estadío de blastocisto con índices reducidos de viabilidad de los mismos. Los avances en el conocimiento de la dinámica celular durante estos procesos condujo a la hipótesis, de que la maduración, entendida como el reinicio del ciclo meiótico, la reorganización del ooplasma y la regulación de la expresión génica, juegan un papel fundamental para sustentar el desarrollo temprano de los embriones, esta capacidad de...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Complejo folicular; Maduración; Meiosis; Ooplasma.
Ano: 2010
URL: http://www.scielo.org.co/scielo.php?script=sci_arttext&pid=S0120-548X2010000300001

Meiotic behavior in Panicum maximum Jacq. (Poaceae: Panicoideae: Paniceae): hybrids and their genitors - doi: 10.4025/actasciagron.v32i3.6461
Provedor de dados: 1
Autores: Pessim, Cleide; UEM; Pagliarini, Maria Suely; UEM; Jank, Liana; Embrapa; Kaneshima, Alice Maria de Souza; Universidade Estadual de Maringá; Bonato, Andréa Beatriz Mendes; Universidade Estadual de Maringá.
Panicum maximum Jacq. is one of the most cultivated grasses in the world. The intraspecific hybridization breeding program underway at Embrapa Beef Cattle aims at combining several agronomic characteristics in a single plant with high seed production. Four intraspecific hybrids originated from the cross between sexual tetraploid female plants with apomictic tetraploid male plants, including the genitors, were cytologically evaluated in the meiotic process throughout conventional methodology. Hybrids and genitors showed high meiotic stability. The percentage of abnormal cells among them ranged from 6.7 to 14.2%. Abnormalities recorded were irregular chromosome segregation, chromosome stickiness, and absence of the first cytokinesis, but the latter did not...
Palavras-chave: 5.01.03.05-9 breeding program; Meiosis; Intraspecific hybrids; Panicum maximum 5.01.03.05-9 breeding program; Meiosis; Intraspecific hybrids; Panicum maximum.
Ano: 2010
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/6461

Comportamento mitótico e meiótico de cromossomos holocêntricos &amp;gama; irradiados de Rhynchospora pubera (Cyperaceae)
Provedor de dados: 3
Autores: Vanzela, André Luís Laforga; UEL; Colaço, Waldeciro; UFPE.
Para avaliar a ocorrência de cinetócoros difusos em Rhynchospora (Cyperaceae), cromossomos de R. pubera foram fragmentados ou fundidos por irradiação &amp;gama;. Este material foi investigado nas gerações celulares subseqüentes, em ambas, mitose e meiose. Alterações no número e no tamanho dos cromossomos foram detectadas, mas o comportamento dos cromossomos irradiados foi normal e nenhum micronúcleo foi observado. Todos os dados apontam para a presença de cinetócoros difusos em R. pubera.
Palavras-chave: 2.00.00.00-6 Ciências Biológicas Cyperaceae; Holocentric chromosomes; Meiosis; Mitosis; Rhynchospora 2.00.00.00-6 Ciências Biológicas.
Ano: 2002
URL: http://periodicos.uem.br/ojs/index.php/ActaSciBiolSci/article/view/2364

Botanical aspects of Heteropterys umbellata (Malpighiaceae): a cytological and palynological approach
Provedor de dados: 42
Autores: Sousa,Saulo M.; Reis,Aryane C.; Gomes,Shaiany S.L.; Bernardo,Karina B.; Salimena,Fátima R.G.; Viccini,Lyderson F.
The genus Heteropterys is one of the major genera in Malpighiaceae. However, few cytological and palynological studies were reported. The present work described for the first time the chromosome number, heterochromatin pattern, meiotic behavior, pollen viability and palynological aspects of Heteropterys ubellata, a very spread species. One large Brazilian population was evaluated using conventional techniques for meiotic studies and acetolyse to access the pollen morphology. The species showed 2n = 20 chromosomes, normal meiotic development and viable pollens. Great blocks of heterochromatin were observed around the centromers. DAPI staining was positive for centroeric heterochroatin, hile CMA3 ark as observed just at terinal regions of one pair of...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Chromosome number; Heterochromatin pattern; Heteropterys umbellata; Malpighiaceae; Meiosis; Pollen viability.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652010000400009

Effect of concentration and exposure period to butyrolactone I on meiosis progression in bovine oocytes
Provedor de dados: 45
Autores: Adona,P.R.; Leal,C.L.V.
The effect of concentration and exposure period of bovine oocytes to butyrolactone I (BLI) on meiotic block and in vitro maturation (IVM) kinetics was studied. In experiment 1, all oocytes were at germinal vesicle stage (GV), after 6h in culture with 0, 50 and 100µM BLI. After 12h, all oocytes cultured with 50 and 100µM BLI remained in GV. After 24h, less oocytes were in GV with 50µM (82%) than with 100µM BLI (99%, P&lt;0.05). In experiment 2, after 6h IVM, 93% of control oocytes (IVM only) were in GV, while treated oocytes (100µM BLI for 6, 12 or 24h prior to IVM) showed less oocytes in GV with increased exposure period to BLI prior to IVM (83 and 73%, for 6h and 12h, P&lt;0.05). For a 24h inhibition, GV rates were similar to 12h (70%, P&gt;0.05). After...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Bovine; Meiosis; Oocyte; Butyrolactone I; Kinetics; Nuclear maturation.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-09352006000300011

Synaptonemal complexes and XY behavior in two species of argentinian armadillos: Chaetophractus villosus and Dasypus hybridus (Xenarthra, Dasypodidae)
Provedor de dados: 47
Autores: Sciurano,R. B.; Merani,M.S.; Bustos,Jimena; Solari,A.J.
Spermatocytes from the two armadillo species, C. villosus and D. hybridus were studied in microspreads for synaptonemal complexes (SCs) and in thin sections for electron microscopy (EM). The complete SC karyotype generally agrees with previous reports on mitotic chromosomes, except for the sex chromosomes. The X chromosome is submetacentric in both species and the Y is the shortest one in C. villosus and the second shortest in D. hybridus, and an extremely acrocentric one. A SC is formed along the total length of the Y chromosome, and this SC persists along all the pachytene substages. A single ecombination nodule (RN) is located in the region of the SC nearest to the attachment to the nuclear envelope. The lateral element (LE) of the X axis in the SC...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Xenarthra; XY chromosomes; Meiosis; Synaptonemal complexes.
Ano: 2006
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S0327-95452006000100009

A male-sterile mutation in soybean (Glycine max) affecting chromosome arrangement in metaphase plate and cytokinesis
Provedor de dados: 47
Autores: Pires Bione,Nilton Cesar; Suely Pagliarini,Maria; Alves de Almeida,Leones.
A spontaneous male-sterile, female-fertile mutation affecting bivalent arrangement at the metaphase plate and cytokinesis was detected in line BR98-197 of the soybean breeding program developed by Embrapa - National Soybean Research Centre. Untill diakinesis, meiosis was normal with chromosome pairing as bivalents. From this phase, in several meiocytes, bivalents were not able to organize a single metaphase plate and remained scattered in the cytoplasm in a few or several groups. In these meiocytes, chromosomes segregated in both divisions giving rise to several micronuclei. However, the main cause of male sterility was the absence of cytokinesis after telophase II. Instead of the typical tetrads of microspores, four nucleate coenocytic microspores were...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Glycine max; Meiosis; Metaphase plate; Cytokinesis; Male sterility.
Ano: 2005
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S0327-95452005000200004

Microsporogenesis in tetraploid accessions of Brachiaria nigropedata (Ficalho &amp;amp; Hiern) Stapf (Gramineae)
Provedor de dados: 47
Autores: Sayuri Utsunomiya,Karina; Suely Paglirini,Maria; Borges do Valle,Cacilda.
The genus Brachiaria (Trin.) Griseb. has achieved considerable importance to cattle production systems, as a result of the good production and adaptation of a few cultivars to poor and acid soils of the Brazilian savannas. Many of its species and accessions are polyploid and apomictic, which limits direct hybridization. To assist the breeding program, cytogenetic characterization has been undertaken on the accessions of Brachiaria collection at the Embrapa Beef Cattle Research Center. In this study, chromosome number and meiotic behavior are reported for the Brachiaria nigropedata (Ficalho &amp;amp; Hiern) Stapf collection. The 20 available accessions are tetraploid (2n = 4x = 36). Chromosomes paired preferentially as bivalents, but quadrivalents were...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Brachiaria nigropedata; Chromosome number; Meiosis; Polyploidy; Apomixis; Grasses.
Ano: 2005
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S0327-95452005000300007

Chromosome number and microsporogenesis of two accessions of Brachiaria dura Stapf (Poaceae)
Provedor de dados: 49
Autores: Risso-Pascotto,Claudiceia; Pagliarini,Maria Suely; Valle,Cacilda Borges do.
The two accessions of B. dura analyzed (DU01 and DU02) are hexaploid (2n = 6x = 54), derived from x = 9. Meiotic abnormalities, such as precocious chromosome migration to the poles, laggards and micronuclei, were recorded in low frequency in both accessions. The few multivalent chromosome association at diakinesis and meiotic stability suggested that hexaploidy probably resulted from chromosome doubling. In DU02, chromosome transfer (cytomixis) among meiocytes, involving part or the entire genome was observed. The implication of these findings for the Brachiaria breeding is discussed.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Brachiaria dura; Meiosis; Chromosome number; Cytomixis.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1676-06032009000200024

Mecanismos citológicos involucrados en la producción de gametos masculinos no reducidos en individuos diploides de Turnera sidoides subsp. carnea (Passifloraceae)
Provedor de dados: 51
Autores: Kovalsky,Ivana Evelin; Fernández,Aveliano; Solís Neffa,Viviana G.
Turnera sidoides (x = 7) es un complejo autopoliploide de hierbas alógamas perennes que incluye cinco subespecies, con niveles de ploidía desde diploide (2n = 2x = 14) hasta octoploide (2n = 8x = 56). Estudios previos aportaron evidencias de la producción de gametos masculinos no reducidos (2n y 4n) en poblaciones diploides del complejo, sugiriendo que los poliploides de T. sidoides habrían surgido por poliploidización sexual. Sin embargo, hasta el momento se desconocen los mecanismos citológicos involucrados en la producción de dichos gametos. Por lo tanto, en este trabajo se analiza el comportamiento meiótico y la viabilidad del polen de individuos productores de gametos no reducidos de una población diploide de T. sidoides subsp. carnea. Los resultados...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Turnera sidoides; Poliploidía; Gametos no reducidos; Meiosis; Viabilidad del polen.
Ano: 2014
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S1851-23722014000200009

Estudios citogenéticos en híbridos triploides y tetraploides de Turnera krapovickasii, T. scabra y T. subulata (Passifloraceae, Turneroideae)
Provedor de dados: 51
A fin de investigar las relaciones genómicas entre especies de la serie Turnera (x= 5), se lleva a cabo un programa de cruzamientos controlados y se obtuvieron numerosos híbridos. Entre las especies con flores amarillas de la serie Turnera, T. krapovickasii, T. scabra y T. subulata poseen citotipos diploide y autotetraploide. Hasta el momento se desconocen el grado de aislamiento reproductivo entre diploides y tetraploides y el grado de afinidad genómica de estas especies a nivel tetraploide. En este trabajo se presentan los resultados del análisis citogenético de los híbridos intraespecíficos triploides (2n=3x=15) de T. krapovickasii y T. scabra y los híbridos tetraploides (2n=4x=20) T. krapovickasii × T. scabra y T. subulata × T. scabra. En los híbridos...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Turnera; Meiosis; Relaciones genómicas; Triploides; Tetraploides.
Ano: 2017
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S1851-23722017000400008

Meiotic behavior during microsporogenesis of Alchornea triplinervia (Sprengel) Müller Argoviensis
Provedor de dados: 65
Autores: Godoy,Sara Mataroli de; Pereira,Andréia Rodrigues Alonso; Romagnolo,Mariza Barion; Risso-Pascotto,Claudicéia.
The Alchornea triplinervia specie belongs to the Euphorbiaceae family, one of the main families of the Brazilian flora. In order to contribute to a better understanding of the specie, a counting of chromosome number and the microsporogenesis analysis of A. triplinervia were done. The inflorescences were collected in the municipalities of Paranavaí and Diamante do Norte, State of Paraná, Brazil, and the slides were prepared by squashing technique and staining with 1% acetic carmine. The analysis were performed using an optical microscope and showed a chromosome number for the specie equal to 2n=8x=72. Irregularities in the chromosome segregation process were the main meiotic abnormalities, presenting typical polyploid behavior. Other irregularities were...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Euphorbiaceae; Chromosome number; 2n gametes; Meiosis; Polyploid.
Ano: 2012
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782012000600012

Chromosome stickiness during meiotic behavior analysis of Passiflora serrato-digitata L. (PassifloraCEAE)
Provedor de dados: 65
Autores: Kiihl,Paulo Roberto Peres; Pereira,Andréia Rodrigues Alonso; Godoy,Sara Mataroli de; Stenzel,Neusa Maria Colauto; Risso-Pascotto,Claudicéia.
Almost 90% of species of the genus Passiflora are native to the American continent, with high commercial value due to the fact that some species are used for human food while others have ornamental and medical qualities. Passiflora serrato-digitata is one of the species that integrates the Paraná Agronomic Institute germoplasm bank at its experimental base in Londrina, PR, Brazil. Collected flower buds were fixed in ethanol/acetic acid (3:1 v/v) for 24h, transferred to 70% alcohol and stored under refrigeration. Slides were prepared by the squashing technique and stained with 1.0% propionic carmine; they were analyzed under an optic microscope. Irregularities in the chromosome segregation process of P. serrato-digitata have been verified by meiotic...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Microsporogenesis; Meiosis; 2n gametes.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782011000600016

Microsporogénesis de tres especies del subgénero Passiflora (Passiflora, Passifloraceae) de Paraguay
Provedor de dados: 66
Autores: Pereira Sühsner,Claudia; Honfi,Ana I; Ferrucci,María S; Deginani,Norma.
El presente trabajo tuvo por objeto caracterizar cariológicamente las especies del género Passiflora L., subgénero Passiflora, del Distrito Félix Pérez Cardozo, Guairá, Paraguay. Por primera vez, se da a conocer el número cromosómico en meiosis 2n = 9II para P. alata Curtis y P. caerulea L. También, se confirma el número cromosómico de 2n = 9II para P. edulis Sims. El comportamiento meiótico en todas las especies estudiadas fue normal, con segregación regular de los cromosomas. La asociación cromosómica frecuentemente encontrada en diacinesis y metafase I fue de bivalentes. Las pocas irregularidades meióticas observadas consistieron en cromosomas rezagados en anafase I y fases asincrónicas en meiosis II, sin embargo, la viabilidad de polen es alta, entre...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Meiosis; Passiflora; Viabilidad del polen.
Ano: 2016
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S0011-67932016000100004

Estudios cromosómicos en especies de Asplenium (Aspleniaceae) de la Argentina
Provedor de dados: 66
Autores: Guillén,Roque H.; Daviña,Julio R.
Documentamos los números cromosómicos meióticos y somáticos de 6 especies del género Asplenium. Se presentan por primera vez los números cromosómicos de A. ulbrichtii var. serrato-dentatum, 2n=2x=72, y A. triquetrum, 2n=4x=144. Reconfirmamos los números cromosómicos de A. auritum, n=72; A. claussenii, 2n=2x=72; A. formosum, n=36; y A. serratum, 2n=8x=288.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Argentina; Asplenium; Números cromosómicos; Helechos; Meiosis; Pteridophyta.
Ano: 2005
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S0011-67932005000100004

Abnormal spindle orientation during microsporogenesis in an interspecific Brachiaria (Gramineae) hybrid
Provedor de dados: 74
Autores: Mendes-Bonato,Andréa Beatriz; Pagliarini,Maria Suely; Valle,Cacilda Borges do.
This paper reports a case of abnormal spindle orientation during microsporogenesis in an interspecific hybrid of the tropical grass Brachiaria. In the affected plant, prophase I was normal. In metaphase I, bivalents were regularly co-oriented but distantly positioned and spread over the equatorial plate. In anaphase I, chromosomes failed to converge into focused poles due to parallel spindle fibers. As a consequence, in telophase I, an elongated nucleus or several micronuclei were observed in each pole. In the second division, the behavior was the same, leading to polyads with several micronuclei. A total of 40% of meiotic products were affected. The use of this hybrid in production systems needing good-quality seeds is discussed.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Brachiaria; Interspecific hybrid; Meiosis; Spindle abnormality; Tropical grass.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572006000100023

Chromosomes of Theridiidae spiders (Entelegynae): interspecific karyotype diversity in Argyrodes and diploid number intraspecific variability in Nesticodes rufipes
Provedor de dados: 74
Autores: Stavale,Leila Miguel; Schneider,Marielle Cristina; Araujo,Douglas; Brescovit,Antonio Domingos; Cella,Doralice Maria.
Theridiidae is a derived family within the Araneoidea clade. In contrast to closely related groups, the 2n(male) = 20+X1X2 with acro/telocentric chromosomes is the most widespread karyotype among the theridiid spiders. In this work, the cytogenetic analysis of Argyrodes elevatus revealed original chromosome features different from those previously registered for Theridiidae, including the presence of 2n(male) = 20+X with meta/submetacentric chromosomes. Most individuals of Nesticodes rufipes showed family conserved karyotype characteristics. However, one individual had a 2n(male) = 24 due to the presence of an extra chromosome pair, which exhibited regular behavior and reductional segregation during meiosis. After silver staining, mitotic cells exhibited...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Chromosome morphology; Cytogenetic; Meiosis; Nucleolar organizer region; Sex chromosome system.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572010000400012

Spermatogenesis and nucleolar activity in Triatoma klugi (triatomine, Heteroptera)
Provedor de dados: 74
Autores: Costa,Laiana Cristina da; Azeredo-Oliveira,Maria Tercília Vilela de; Tartarotti,Ester.
Triatoma klugi is a Chagas disease vector in the Rio Grande do Sul State. Triatominae chromosomes are holocentric and sex chromosomes segregation is post-reductional. In this paper we describe the karyotype of male T. klugi and a meiotic analysis including the nucleolar behavior during spermatogenesis. Testis cells were analyzed after lacto-acetic orcein and silver nitrate staining. Two autosomes and the heterochromosomes presented nucleolar activity (Ag-NORs) during diplotene-diakinesis. The analysis of metaphase I and II revealed a karyotype with 2n = 20+XY. In metaphase I a prominent nucleolar mass was observed in the cell periphery and small silver grains were detected in metaphase II. During anaphase, the chromosomes segregated in parallel and a...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Triatoma klugi; Triatomine; Cytogenetics; Nucleolus; Karyotype; Meiosis.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000300008

Chromosome complement and meiosis in three species of the Neotropical bug genus Antiteuchus (Heteroptera, Pentatomidae, Discocephalinae)
Provedor de dados: 74
Autores: Lanzone,Cecilia; Souza,Maria José de.
Orcein staining of spermatocytes was used to study the meiotic behavior of holocentric chromosomes in three member of the genus Antiteuchus (commonly known as stink bugs). We describe and illustrate the karyotype of Antiteuchus mixtus, A. sepulcralis and A. macraspis which were cytogenetically characterized as having a diploid number of 2n = 14 and an XY sex chromosome system showing pre-reductional meiosis for autosomes and post-reductional meiosis for sex chromosomes. These species were also shown to have a long diffuse stage during meiotic prophase I and aberrant harlequin-type meiocytes. The chiasma frequency was also analyzed for two of the three species studied.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Spermatogenesis; Holokinetic chromosomes; Sex chromosomes; Meiosis; Diffuse stage.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572006000100011

Karyotype differentiation in three species of Tripogandra Raf. (Commelinaceae) with different ploidy levels
Provedor de dados: 74
Autores: Marques,André; Roa,Fernando; Guerra,Marcelo.
Most species of the genus Tripogandra (Commelinaceae) are taxonomically poorly circumscribed, in spite of having a relatively stable basic number x = 8. Aiming to estimate the cytological variation among Tripogandra species carrying this base number, several structural karyotypic characters were investigated in the diploid T. glandulosa, the hexaploid T. serrulata, and the octoploid T. diuretica. A careful evaluation of chromosome size and morphology did not reveal clear chromosome homeologies among karyotypes. The mean chromosome size was strongly reduced in the octoploid species, but not in the hexaploid species. They also differed largely in the CMA+ banding pattern and in the number of 5S and 45S rDNA sites per monoploid chromosome complement. All...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Tripogandra; Cytotaxonomy; RDNA sites; CMA/DAPI bands; Meiosis.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572010000400020

Astylus variegatus (Coleoptera, Melyridae): Cytogenetic study of a population exposed to agrochemical products
Provedor de dados: 74
Autores: Schneider,Marielle Cristina; Carraro,Bianca Pierina; Cella,Doralice Maria; Matiello,Rodrigo Rodrigues; Artoni,Roberto Ferreira; Almeida,Mara Cristina.
In this work we describe the cytogenetic analyses performed in specimens of Astylus variegatus (Germar, 1824) collected in two localities: one area of natural vegetation and one of agricultural crops, where agrochemical products were used. Astylus variegatus had karyotypes with 2n(male) = 16+Xy p and 2n (female) = 16+XXp, with exclusively metacentric chromosomes. Pachytene spermatocytes showed synapsed autosomal bivalents and non-associated sex chromosomes. In diplotene, the autosomal bivalents exhibited one or two terminal chiasmata and the Xy p had a typical parachute configuration. In meiotic cells of some specimens, an extra chromosome, interpreted as a B chromosome, was observed. C-banding showed constitutive heterochromatin in the pericentromeric...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: B chromosome; Constitutive heterochromatin; Karyotype; Meiosis; Ag-NORs.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572007000400023

X1X1X2X2/X1X2Y sex chromosome systems in the Neotropical Gymnotiformes electric fish of the genus Brachyhypopomus
Provedor de dados: 74
Autores: Cardoso,Adauto Lima; Pieczarka,Julio Cesar; Nagamachi,Cleusa Yoshiko.
Several types of sex chromosome systems have been recorded among Gymnotiformes, including male and female heterogamety, simple and multiple sex chromosomes, and different mechanisms of origin and evolution. The X1X1X2X2/X1X2Y systems identified in three species of this order are considered homoplasic for the group. In the genus Brachyhypopomus, only B. gauderio presented this type of system. Herein we describe the karyotypes of Brachyhypopomus pinnicaudatus and B. n. sp. FLAV, which have an X1X1X2X2/X1X2Y sex chromosome system that evolved via fusion between an autosome and the Y chromosome. The morphology of the chromosomes and the meiotic pairing suggest that the sex chromosomes of B. gauderio and B. pinnicaudatus have a common origin, whereas in B . n....
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Sex chromosome fusion; Sexual trivalent; Meiosis.
Ano: 2015
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572015000200213

Cytogenetic studies of three Lycosidae species   from Argentina (Arachnida, Araneae)
Provedor de dados: 74
Autores: Chemisquy,María A.; Gil,Sergio G. Rodríguez; Scioscia,Cristina L.; Mola,Liliana M.
Cytogenetic studies of the family Lycosidae (Arachnida: Araneae) are scarce. Less than 4% of the described species have been analyzed and the male haploid chromosome numbers ranged from 8+X 1  X  2  to 13+X 1  X  2 . Species formerly classified as  Lycosa  were the most studied ones. Our aim in this work was to perform a comparative analysis of the meiosis in " Lycosa "  erythrognatha  Lucas, " Lycosa "  pampeana  Holmberg and  Schizocosa malitiosa  (Tullgren). We also compared male and female karyotypes and characterized the heterochromatin of " L. "  erythrognatha . The males of the three species had 2n = 22, n = 10+X 1 X 2 , all the chromosomes were telocentric and there was generally a single chiasma per bivalent. In " Lycosa "  pampeana , which is...
Palavras-chave: Meiosis; C-banding; Fluorochrome staining; Karyotype; Spiders; "Lycosa"  and Schizocosa.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000500010

Meiosis in elephant grass (Pennisetum purpureum), pearl millet (Pennisetum glaucum) (Poaceae, Poales) and their interspecific hybrids
Provedor de dados: 74
Autores: Techio,Vânia Helena; Davide,Lisete Chamma; Pereira,Antônio Vander.
The cultivated and sexually compatible species Pennisetum purpureum (elephant grass, 2n = 4x = 28) and Pennisetum glaucum (pearl millet, 2n = 2x = 14) can undergo hybridization which favors the amplification of their genetic background and the introgression of favorable alleles into breeding programs. The main problem with interspecific hybrids of these species is infertility due to triploidy (2n = 3x = 21). This study describes meiosis in elephant grass x pearl millet hybrids and their progenitors. Panicles were prepared according to the conventional protocol for meiotic studies and Alexander’s stain was used for assessing pollen viability. Pearl millet accessions presented regular meiosis with seven bivalents and high pollen viability. For elephant...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Meiosis; Pennisetum; Elephant grass; Interspecific hybrids; Pearl millet; Pollen.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572006000200025

Combined association of Presenilin-1 and Apolipoprotein E polymorphisms with maternal meiosis II error in Down syndrome births
Provedor de dados: 74
Autores: Bhaumik,Pranami; Ghosh,Priyanka; Ghosh,Sujay; Feingold,Eleanor; Ozbek,Umut; Sarkar,Biswanath; Dey,Subrata Kumar.
Abstract Alzheimer's disease and Down syndrome often exhibit close association and predictively share common genetic risk-factors. Presenilin-1 (PSEN-1) and Apolipoprotein E (APOE) genes are associated with early and late onset of Alzheimer's disease, respectively. Presenilin −1 is involved in faithful chromosomal segregation. A higher frequency of the APOE ε4 allele has been reported among young mothers giving birth to Down syndrome children. In this study, 170 Down syndrome patients, grouped according to maternal meiotic stage of nondisjunction and maternal age at conception, and their parents were genotyped for PSEN-1 intron-8 and APOE polymorphisms. The control group consisted of 186 mothers of karyotypically normal children. The frequencies of the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Chromosome; Genetic polymorphism; Karyotype; Meiosis; Microsatellite markers.
Ano: 2017
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572017000400577

Cytogenetic analysis of Astylus antis (Perty, 1830) (Coleoptera, Melyridae): Karyotype, heterochromatin and location of ribosomal genes
Provedor de dados: 74
Autores: Mendes-Neto,Ernani de Oliveira; Vicari,Marcelo Ricardo; Campaner,Carlos; Nogaroto,Viviane; Artoni,Roberto Ferreira; Almeida,Mara Cristina.
Cytogenetic analysis of Astylus antis using mitotic and meiotic cells was performed to characterize the haploid and diploid numbers, sex determination system, chromosome morphology, constitutive heterochromatin distribution pattern and chromosomes carrying nucleolus organizer regions (NORs). Analysis of spermatogonial metaphase cells revealed the diploid number 2n = 18, with mostly metacentric chromosomes. Metaphase I cells exhibited 2n = 8II+Xyp and a parachute configuration of the sex chromosomes. Spermatogonial metaphase cells submitted to C-banding showed the presence of small dots of constitutive heterochromatin in the centromeric regions of nearly all the autosomes and on the short arm of the X chromosome (Xp), as well as an additional band on one of...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Sex chromosomes; Meiosis; Metaphase; FISH; 18S rDNA.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572010000200007

Spermatogenesis of Zaprionus indianus and Zaprionus sepsoides (Diptera, Drosophilidae): cytochemical, structural and ultrastructural characterization
Provedor de dados: 74
Autores: Rego,Letícia do Nascimento Andrade de Almeida; Silistino-Souza,Rosana; Azeredo-Oliveira,Maria Tercília Vilela de; Madi-Ravazzi,Lilian.
Zaprionus indianus is a drosophilid native to the Afrotropical region that has colonized South America and exhibits a wide geographical distribution. In contrast, Z. sepsoides is restricted to certain African regions. The two species differ in the size of their testes, which are larger in Z. indianus than in Z. sepsoides. To better understand the biology and the degree of differentiation of these species, the current study evaluated spermatogenesis in males of different ages by conventional staining techniques and ultrastructural analysis. Spermatogenesis and the ultrastructure of spermatozoa were similar in the two species, and the diploid number was confirmed to be 2n = 12. A greater number of spermatozoa were observed in young Z. indianus (1-3 days old)...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Zaprionus indianus; Zaprionus sepsoides; Spermatogenesis; Cytochemistry; Ultrastructure; Meiosis.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572013000100008

Cytological analysis of hybrids among triticales and trigopiros
Provedor de dados: 74
Autores: Fradkin,Maia; Greizerstein,Eduardo; Paccapelo,Héctor; Ferreira,Víctor; Grassi,Ezequiel; Poggio,Lidia; Ferrari,María Rosa.
We studied three different tricepiros: (Don Santiago x Don Noé), (Cumé x Horovitz) and (Cumé x Don Noé). The tricepiro (Don Santiago x Don Noé) was obtained by crossing the triticale Don Santiago INTA (AABBRR, 2n = 6x = 42) with the trigopiro Don Noé INTA (AABBDDJJ, 2n = 8x = 56). The number of chromosomes for the F1 was 2n = 49, the most frequent meiotic configuration being 14 bivalents and 21 univalents. The univalents were situated in the periphery of the equatorial plane, whereas the bivalents were located in the central zone. The chromatids in some of the univalents split when bivalents underwent reductional division in anaphase I. There were few laggard chromosomes or chromatids at this phase. The number of chromosomes (2n = 48-58) was high and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Hybrids; Meiosis; Tricepiro; Univalents; Reductional division.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572009000400022

True polyploid meiosis in the human male
Provedor de dados: 74
Autores: Pearson,Peter L.; Madan,Kamlesh.
Abstract Polyploidy does not usually occur in germinal cells of mammals and other higher vertebrates. We describe a unique example of mosaic autotetraploidy in the meiosis of a human male. Although the original observations were made in the late 1960s, we did not publish them at that time, because we expected to detect further examples that could be described together. However, this did not occur and we have now decided to make the observations available to demonstrate that polyploidy in mammalian male meiosis can arise at a higher frequency than expected by random polyploidization of individual meiotic cells, by either DNA duplication or cell fusion prior to synapsis. This is the first description of a population of primary spermatocytes exhibiting...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Polyploidy; Meiosis; Human; Male.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572018000300410

Karyotypes of two cytotypes of Paspalum quadrifarium Lam. (Poaceae): an alternative technique for small chromosomes in plants
Provedor de dados: 74
Autores: Speranza,Pablo; Vaio,Magdalena; Mazzella,Cristina.
Paspalum quadrifarium Lam. is a bunchgrass native to Uruguay, Argentina, and southern Brazil. Diploid, triploid, tetraploid and hexaploid cytotypes have been reported for this species of the Quadrifaria group of Paspalum. In this group, a high degree of cytogenetic homology between the genomes of several diploid species has been reported, based on meiotic pairing in interspecific hybrids; multivalent associations would thus be expected in polyploid hybrids. Karyotype analysis could provide useful information about the genomic architecture of polyploid plants; however, the fully condensed mitotic chromosomes of Paspalum do not provide enough morphological features for such an analysis. In this paper, we used mitotic prometaphase chromosomes treated with 70%...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Karyotype; Meiosis; Prometaphase; Grasses; Paspalum.
Ano: 2003
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572003000400013

Cytogenetic study of the genus Cousinia (Asteraceae, section Serratuloideae) in Iran
Provedor de dados: 74
Autores: Sheidai,Masoud; Mehdigholi,Kazem; Ghahreman,Ahmad; Attar,Farideh.
Meiotic studies of ploidy level, chromosome paring and chiasma frequency were performed on 11 Cousinia (Asteraceae) species of the section Serratuloideae. The diploid number of the species studied was 2n = 2x = 24 and 26 so these species possess two different basic numbers (x = 12 or 13), a phenomenon common to other sections of the genus. The chromosome numbers of 9 species are reported here for the first time. When the 2n = 24 and 2n = 26 species were subjected to cluster analysis based on relative meiotic characters two different clusters were formed indicating their distinctness. Our data support the results obtained from morphometry, anatomy, pollen morphology and molecular studies of the genus Cousinia.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Cousinia; Chiasma frequency; Cluster analysis; Meiosis.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572006000100022

Meiotic behavior and fertility of Capsicum interspecific hybrids
Provedor de dados: 75
Autores: Oliveira,Sara I de; Ribeiro,Elba H; Moreira,Nádia F; Vianna,Larissa S; Pereira,Telma NS.
ABSTRACT This study was performed to evaluate the meiotic behavior and fertility of four hybrids obtained from the crossing of Capsicum baccatum and its botanical forms with Capsicum chinense and Capsicum frutescens. We aimed to identify the causes of the low fertility in interspecific hybrids involving species from different gene pools of Capsicum. Hybrid flower buds were fixed in fixative solution and the slides were prepared using 1%-acetic carmine solution. Meiosis was observed in all phases and the main meiotic abnormality observed was the complete or partial lack of chromosome pairing, indicating that the species are either genetically distant or that some asynaptic gene was present in the hybrids. Meiotic index (MI), the frequency of unreduced...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Capsicum baccatum; Capsicum chinense; Capsicum frutescens; Meiosis; Meiotic abnormality; Chromosome pairing.
Ano: 2020
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-05362020000400382

Comportamento citológico atípico durante a microsporogênese em Brachiaria ruziziensis e B. decumbens.
Provedor de dados: 14
Autores: RISSO-PASCOTTO, C.; MENDES-BONATO, A. B.; PAGLIARINI, M. S.; VALLE, C. B. do.
Em gramíneas forrageiras do gênero Brachiaria, populações poliplóides naturais são abundantes e geralmente apomíticas, enquanto as diploídes, que se reproduzem sexualmente, são raras. Considerando-se a estreita correlação existente entre poloploidia e apomixia neste gênero, e a necessidade de identificação de genótipos sexuais compatíveis para o sucesso de hibridação, conhecimentos de características citológicas básicas como modo de reprodução, comportamento meiótico e nível de ploidia tornam-se essenciais para direcionar os programas de melhoramento. Durante análises desenvolvidas na Universidade Estadual de Maringá, com acessos de várias espécies de uma coleção de germoplasma, mantida na Embrapa Gado de Corte, três acessos, sendo um B....
Tipo: Folhetos
Palavras-chave: Braquiária; Feed grasses; Brachiaria Decumbens; Brachiaria Ruziziensis; Citogenética Vegetal; Gramínea Forrageira; Meiose; Poliploidia; Cytogenetics; Meiosis; Polyploidy.
Ano: 2003
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/324062

Variaciones meióticas y evolución cromosómica en insectos y arácnidos con cromosomas holocinéticos
Provedor de dados: 46
Autores: Mola,L. M; Rebagliati,P. J; Rodríguez Gil,S. G; Adilardi,R. S.
Los estudios citogenéticos en grupos modelo de insectos (Odonata y Heteroptera) y arácnidos (Dysderoidea y Buthidae) con cromosomas holocinéticos nos han permitido determinar diferencias en el comportamiento meiótico de autosomas y cromosomas sexuales (meiosis pre- o post-reduccional, quiasmática o aquiasmática, actividad telocinética u holocinética) y en la frecuencia y distribución de las mutaciones cromosómicas (fusiones, fragmentaciones y translocaciones en homocigosis o heterocigosis) en la evolución del cariotipo.
Tipo: Info:eu-repo/semantics/report
Palavras-chave: Cromosomas holocinéticos; Meiosis; Evolución cromosómica; Odonata; Heteroptera; Dysderoidea; Buthidae.
Ano: 2011
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S1852-62332011000100012

Pollen viability and meiotic irregularities in a collection of Stevia rebaudiana (Bertoni) Bertoni cultivated in Tucumán, Argentina
Provedor de dados: 46
Autores: Budeguer,C.J; Camadro,E.L; Erazzú,L.E.
Stevia rebaudiana (Bertoni) Bertoni (2n=2x=22) (Asteraceae family) is a species of economic value due to the presence of steviol glycosides in leaves -mainly stevioside and rebaudioside A- which are non-caloric sugars. In 2013, a collection of plants (genotypes) from four contrasting environments was established in Tucuman, Argentina, for evaluation under local conditions and, eventually, breeding purposes. As a first step, pollen viability and meiosis was studied in a sample of 56 plants. The percentage of pollen viability varied from medium (69.4%) to high (99.6%) in 52 of them, but from low (36.5%) to relatively low (51.5%) in the remaining four. The latter four plants also presented pollen grains of heterogeneous size, which were classified as n...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Stevia; Pollen viability; Meiosis; Sporads.
Ano: 2018
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S1852-62332018000200005

C-Banding patterns and meiotic behavior in Hypsiboas pulchellus and H. Cordobae (anura, hylidae)
Provedor de dados: 46
Autores: Baraquet,M; Salas,N.E; Martino,A.L.
In this work, we observed and evaluated C-banding patterns and meiotic behaviour of Hypsiboas pulchellus and H. cordobae. Twenty metaphasic cells per individual were analyzed, which were obtained from intestinal and testis cells using conventional and C-banding techniques. The two species presented 2n= 24 chromosomes. Pairs 1 and 8 to 12 were metacentric whereas pairs 2 to 7 were submetacentric. The centromeric region of all chromosomes was positively C-banded but the C-banding pattern varied between species. At meiosis, cells with 12 bivalents were observed. Bivalents usually presented two terminal chiasmata, although the largest pair presented only one terminal chiasma. The cytogenetic data reconfirms the diploid somatic chromosome number of H....
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Karyotypes; C-banding; Meiosis; Hypsiboas pulchellus; Hypsiboas cordobae.
Ano: 2013
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S1852-62332013000100005

Use of 2n pollen in generating interspecific derivatives of groundnut
Provedor de dados: 30
Autores: Mallikarjuna, N.
Palavras-chave: Genomes; Polyploidy; Nucleus; Hybrids; Chromosome number; Chromosomes; Mosses; Meiosis; Cytogenetics; DNA.
Ano: 2006
URL: http://agropedia.iitk.ac.in/openaccess/?q=node/3176

Abnormal meiotic behavior in three species of Crotalaria
Provedor de dados: 86
Autores: Ferreira,Kátia; Torres,Giovana Augusta; Carvalho,Isabelle Vilela de; Davide,Lisete Chamma.
The objective of this work was to compare the meiotic behavior and pollen grain viability of three species of Crotalaria. Slides for meiotic analysis were prepared by the air-drying technique. Pollen grain viability was measured by three staining procedures (Alexander's solution, tetrazolium chloride and fluorescein diacetate) and in vitro germination in a sucrose solution. Eight bivalents were observed, confirming previous reports on populations from other regions of Brazil, as well as from other countries. All species showed abnormal meiotic behavior as follows: in Crotalaria micans, cytomixis and abnormal chromosome pairing in diakinesis; in C. spectabilis, abnormal chromosome pairing in diplotene; in C. zanzibarica, shrunk nuclei in leptotene and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Crotalaria; Cytogenetics; Cytomixis; Meiosis; Pollen grain viability.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2009001200012

Estudio de los cromosomas mitóticos y meióticos del sotol (Dasylirion cedrosanum Trel.)
Provedor de dados: 85
Autores: Hernández-Quintero,JD; Reyes-Valdés,MH; Mendoza-Rodríguez,DV; Gómez-Martínez,M; Rodríguez-Herrera,R.
El género Dasylirion es un grupo de plantas típicas del Desierto Chihuahuense, perennes, de un comportamiento sexual dioico y denominadas comúnmente sotoles. Es un género poco estudiado desde el punto de vista biológico y se desconocen las bases de su dinámica reproductiva. En este trabajo se estudió el número cromosómico y el comportamiento meiótico de Dasylirion cedrosanum en el municipio de Saltillo, Coahuila, una localidad del noreste de México. Para la preparación de cromosomas mitóticos se utilizó una técnica basada en un tratamiento enzimático con pectoliasa y celulasa, así como tinción con acetocarmín. Para el estudio meiótico se recolectaron botones florales masculinos, se fijaron y se tiñeron con el mismo colorante. Como resultado, se reportan...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Dasylirion cedrosanum; Dioecia; Cromosomas; Mitosis; Meiosis.
Ano: 2015
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S1851-56572015000100015

New contributions to the study of Corixoidea: cytogenetic characterization of three species of Sigara from Argentina and the plausible mechanisms of karyotype evolution within Nepomorpha
Provedor de dados: 99
Autores: Bressa,María José; Papeschi,Alba Graciela.
Cytogenetic studies in Heteroptera contribute to the analysis of evolutionary trends within the group. Heteroptera are characterized by the possession of holokinetic chromosomes, different sex chromosome mechanisms and a pair of m chromosomes in some species. In the present work, the male karyotype and meiosis in Sigara denseconscripta (Breddin), S. chrostowskii Jaczewski, and S. rubyae (Hungerford) are described. The three species share a diploid chromosome number of 2n= 24 with a pair of m chromosomes and an XY/XX sex chromosome system. With this study the chromosome number of 30 species of Corixoidea are known and the modal karyotype is 2n= 20+2m+XY in males. The available cytogenetic information in Heteroptera led us to suggest that the presence of a...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Cytogenetics; Heteroptera; Holokinetic chromosomes; Meiosis; M chromosomes.
Ano: 2007
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S0373-56802007000200010

Microsporogenesis in Brachiaria bovonei (Chiov.) Robyns and B. subulifolia (Mez) Clayton (Poaceae)
Provedor de dados: 63
Autores: Risso-Pascotto,Claudicéia; Pagliarini,Maria Suely; Valle,Cacilda Borges do.
Some African species of Brachiaria have been introduced into the Americas and became the most important forage for pastures in the tropics. New cultivars can be obtained either from direct selections from the natural existing variability in the germplasm collections or from interspecific hybridizations. Polyploidy is predominant in the genus Brachiaria and correlated with apomixis which complicates hybridization. The objective of cytological studies underway on the Brachiaria germplasm collection at Embrapa Beef Cattle is to determine the chromosome number and meiotic behavior of accessions. For the breeding of Brachiaria species, compatible sexual and apomictic accessions need to be identified. Microsporogenesis was evaluated in two accessions of...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Brachiaria; Meiosis; Chromosome number; Polyploidy; Breeding program.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162009000500015

Meiotic behavior of interspecific hybrids between artificially tetraploidized sexual Brachiaria ruziziensis and tetraploid apomictic B. brizantha (Poaceae)
Provedor de dados: 63
Autores: Felismino,Mariana Ferrari; Pagliarini,Maria Suely; Valle,Cacilda Borges do.
The meiotic behavior of four interspecific promising hybrids was evaluated by conventional cytological methods. The female genitors were two artificially tetraploidized sexual accessions of B. ruziziensis (R41 and R44, 2n = 4χ = 36), which were crossed to an agronomically superior natural tetraploid apomictic genotype of B. brizantha (B140 - BRA003395). Three of them (HBGC313, HBGC 315, and HBGC324) were sexual and one (HBGC325) apomictic. Analyses of some cells in diakinesis revealed multivalent chromosome configurations, suggesting that genetic recombination and introgression of some genes could be present. The four hybrids had different types of meiotic abnormalities at various frequencies. Abnormalities related to irregular chromosome segregation due...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Brachiaria; Brazil; Cytogenetics; Forage grasses; Meiosis.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162010000200010

Influence of high temperature on the reproductive biology of dry edible bean (Phaseolus vulgaris L.)
Provedor de dados: 63
Autores: Silva,Daiana Alves da; Pinto-Maglio,Cecília Alzira Ferreira; Oliveira,Érica Cristina de; Reis,Raquel Luiza de Moura dos; Carbonell,Sérgio Augusto Morais; Chiorato,Alisson Fernando.
ABSTRACT: The aim of this study was to investigate the effect of heat stress on 12 bean genotypes through the analysis of their reproductive biology in terms of flowering, pollen viability, meiotic behavior, and production. Plants were grown in a climate chamber at 25-20 °C (day and night) and at a high temperature treatment 37-26 °C (day and night) from the vegetative (V4) development stage to physiological maturity. The experimental design was 2 × 12 factorial arrangement with six replications and the factors consisted of heat treatments and genotypes. In three replications, the number of newly opened flowers was checked daily. At physiological maturity, the following traits were evaluated: percentage of pod set, number of pods, number of viable seeds,...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Common bean; Heat stress; Pollen viability; Meiosis; Seed yield.
Ano: 2020
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162020000301100

Interspecific hybrids between Paspalum plicatulum and P. oteroi: a key tool for forage breeding
Provedor de dados: 63
Autores: Novo,Patricia Elda; Valls,José Francisco Montenegro; Galdeano,Florencia; Honfi,Ana Isabel; Espinoza,Francisco; Quarin,Camilo Luis.
ABSTRACT Grama-tio-pedro (Paspalum oteroi Swallen) is a rare stoloniferous grass of the Plicatula group of Paspalum, well adapted to continuous grazing in areas subject to seasonal flooding in the Pantanal region, in central western Brazil. The species is a facultative apomictic (asexual reproduction by seed) tetraploid, sporadically cultivated on Pantanal farms, propagated either by cuttings or seed. Due to its potential for extensive cultivation and forage quality, Grama-tio-pedro appears as a candidate for genetic improvement within the Plicatula group through plant breeding. We used a colchicine-induced sexual autotetraploid genotype of P. plicatulum Michx. to obtain interspecific hybrids using the apomictic species, P. oteroi, as pollen donor. The...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: DNA content; Apomixis; Fertility; Meiosis; Reproductive mode.
Ano: 2016
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162016000400356