Nova técnica para a contagem de cromossomos em amendoim (Arachis Hypogaea L.)

Medina, Dixier M.; Conagin, Cândida H. T. Mendes

doi:10.1590/s0006-87051963000100042

Cited by 7 publications

(6 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Chromosome spreading depends, to a certain extent, upon the duration of the pretreatment: 8 h of Pdb or Oq and 4 h of Co produced greater number of well scattered prophases and prometaphases in embryos of comparable sizes. The variation observed is probably related to the mitotic activity of the embryo, as has been discussed before in similar treatments for roots (MEDINA and CoNAGIN 1963 ).…”

Section: Resultssupporting

confidence: 57%

Technique For Chromosome Observation inCoffeaEmbryos

Medina¹,

Conagin²,

Longo³

1971

Caryologia

Self Cite

View full text Add to dashboard Cite

Section: Resultssupporting

confidence: 57%

Technique For Chromosome Observation inCoffeaEmbryos

Medina¹,

Conagin²,

Longo³

1971

Caryologia

Self Cite

View full text Add to dashboard Cite

“…Cytological preparations were made by squashing the anthers in 1.2% acetic carmine (Medina and Conagin, 1964). This same technique was used to verify the normality of microspore tetrads and the viability of pollen grains.…”

Section: Methodsmentioning

confidence: 99%

Chromosome studies on Brazilian cerrado plants

Forni‐Martins

Martins

2000

Genet. Mol. Biol.

View full text Add to dashboard Cite

Cerrado is the Brazilian name for the neotropical savanna, which occurs mainly in Brazilian Central Plateau, composed of herbaceous-subshrubby and shrubby-arboreal floras, both of which are heliophilous, highly diverse and regionally differentiated. Considering species distribution and chromosome numbers, some authors have proposed that the herbaceous-subshrubby flora of the neotropical savanna is quite old, while the shrubby-arboreal flora is derived from forests, a hypothesis that implies higher chromosome numbers in the savanna than in the forest. If, however, chromosome numbers are similar in the cerrado and in forests, both could be similarly old, indicating that bi-directional flow of flora occurred in the past. This paper presents data on chromosome numbers and microsporogenesis for 20 species in 13 families collected in the States of São Paulo, Goiás and Minas Gerais, providing previously unpublished data for Myrcia (Myrtaceae), Luxemburgia (Ochnaceae) and Hortia (Rutaceae). Meiosis proved to be normal, indicating regularity in the sexual reproductive process. Chromosome numbers varied from 2n = 18 (Allamanda angustifolia: Apocynaceae) to 2n = ca. 104 (Ouratea spectabilis: Ochnaceae), being low (20 < 2n < 30) in most of the species. Since similar numbers have been observed with forest species, it is not, at the moment, possible to support the hypothesis that cerrado species derived from the surrounding forests. Instead, we suggest the possibility of a bi-directional exchange of floristic elements between cerrado and forests during evolutionary time.
Cerrado é a palavra que, no Brasil, designa a savana neotropical, com área nuclear no Planalto Central, constituída de uma flora herbáceo-subarbustiva e outra arbustivo-arbórea, ambas heliófilas, altamente diversificadas e regionalmente diferenciadas. Considerando a distribuição de espécies e de números cromossômicos, alguns autores propuseram que a flora herbáceo-subarbustiva da savanna neotropical seria bastante antiga, enquanto a flora arbustivo-arbórea seria derivada das florestas Atlântica e Amazônica, uma hipótese que implica na ocorrência de números cromossômicos mais altos no cerrado que nas florestas. Porém, se os números cromossômicos forem similares no cerrado e nas florestas, ambos os tipos de formação poderiam ser similarmente antigos, indicando que um fluxo florístico bidirecional entre o cerrado e as florestas teria ocorrido no passado. Este trabalho apresenta dados sobre números cromossômicos e microsporogênese de 20 espécies em 13 famílias, coletadas nos estados de São Paulo, Goiás e Minas Gerais, trazendo informações inéditas para Myrcia (Myrtaceae), Luxemburgia (Ochnaceae) e Hortia (Rutaceae). A meiose mostrou-se normal, indicando regularidade no processo reprodutivo sexual. Os números cromossômicos variaram de 2n = 18 (Allamanda angustifolia: Apocynaceae) a 2n = ca. 104 (Ouratea spectabilis: Ochnaceae), sendo baixos (20 < 2n < 30) na maioria das espécies. Como números cromossômicos similares têm sido encontrados também em espécies flores...

show abstract

“…Cytological preparations were obtained using the Giemsa technique (Guerra, 1983). For meiotic analysis, floral buds were fixed in ethanol-acetic acid (3:1, v/v) for approximately 24 h and the anthers then squashed onto slides in acetic carmine (Medina and Conagin, 1964).…”

Section: Mitotic and Meiotic Studiesmentioning

confidence: 99%

“…Tetrad analysis and pollen viability were assessed as described by Medina and Conagin (1964). The technique of Alexander (1980) was also used to estimate pollen viability in order to allow comparison between the results obtained with both techniques (Dafni, 1992).…”

Section: Tetrad Analysis and Pollen Viabilitymentioning

confidence: 99%

Chromosomal and morphological studies of diploid and polyploid cytotypes of Stevia rebaudiana (Bertoni) Bertoni (Eupatorieae, Asteraceae)

et al. 2004

View full text Add to dashboard Cite

In this study, we examined the chromosome number and some morphological features of strains of Stevia rebaudiana. The chromosomes were analyzed during mitosis and diakinesis, and the tetrad normality and pollen viability were also assessed. In addition, stomata and pollen were measured and some plant features were studied morphometrically. All of the strains had 2n = 22, except for two, which had 2n = 33 and 2n = 44. Pairing at diakinesis was n = 11 II for all of the diploid strains, whereas the triploid and tetraploid strains had n = 11 III and n = 11 IV , respectively. Triploid and tetraploid plants had a lower tetrad normality rate than the diploids. All of the strains had inviable pollen. Thus, the higher the ploidy number, the greater the size of the pollen and the stomata, and the lower their number per unit area. The triploid strain produced the shortest plants and the lowest number of inflorescences, whereas the tetraploid strain had the largest leaves. Analysis of variance revealed highly significant differences among the strains, with a positive correlation between the level of ploidy and all of the morphological features examined.

show abstract

Nova técnica para a contagem de cromossomos em amendoim (Arachis Hypogaea L.)

Cited by 7 publications

References 12 publications

Technique For Chromosome Observation inCoffeaEmbryos

Technique For Chromosome Observation inCoffeaEmbryos

Chromosome studies on Brazilian cerrado plants

Chromosomal and morphological studies of diploid and polyploid cytotypes of Stevia rebaudiana (Bertoni) Bertoni (Eupatorieae, Asteraceae)

Contact Info

Product

Resources

About