Research Article

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Brachiaria; chromosome elimination; Meiosis; mitosis

Three accessions of Brachiaria brizantha, three of B. humidicola, and two interspecific hybrids between B. ruziziensis and B. brizantha were analyzed with regard to their mitotic behavior in root tips. All these genotypes revealed chromosome elimination or lack of chromosome affinity in previous analyses of microsporogenesis. Analyses of root tips showed a ... more

M.F. Felismino; N. Silva; M.S. Pagliarini; C.B. Valle
Cytogenetics; Holocentric chromosomes; Meiosis; Nucleolus; Spermatogenesis; Triatomines

Triatomines are of great concern in public health because they are vectors of Chagas’ disease. This study presents an analysis of the species Triatoma melanosoma. The cytogenetic characteristics of triatomines include holocentric chromosomes, post-reductional meiosis in the sex chromosomes and nucleolar fragmentation in the meiotic cycle. The methodology utilized consisted of the ... more

V.B. Bardella; M.T.V. Azeredo-Oliveira; E. Tartarotti
Meiosis; Moringa oleifera; Pollen viability; Tripolar spindles; Unreduced gametes

Although originally from India, Moringa oleifera is now cultivated throughout most of the tropics, including Brazil. Despite its multipurpose value for food and traditional medicine, little is known about the meiotic behavior and pollen viability of M. oleifera. We evaluated microsporogenesis and pollen viability in eleven plants grown in southern Brazil (Maringá, Paraná ... more

N. Silva; A.B. Mendes-Bonato; J.G.C. Sales; M.S. Pagliarini
Acledra; Heteroptera; Holokinetic chromosomes; Karyotypic variation; Meiosis; Pentatomidae

Acledra comprises 15 taxonomically identified species, most of which are crop pests. This is the first cytogenetic study of species of this genus. Acledra kinbergii and A. modesta showed the modal number of the Pentatomidae (2n = 14 = 12 + XY), while A. bonariensis had a reduced complement (2n = 12 = 10 + XY), with a markedly larger autosomal ... more

P.J. Rebagliati; L.M. Mola
2n gamete; Interspecific hybridization; Meiosis; Pentaploidy; Poaceae

Knowledge about the cytology and reproductive behavior of a species is indispensable for hybridization programs. This is especially true for species belonging to the genus Paspalum, among which apomixis and a wide range of ploidy levels are frequently found. Paspalum conspersum Schrad. is a robust and warm-season perennial bunchgrass native to South America. Previous ... more

L. Janke; F.H.D. Souza; J.F.M. Valls; M.S. Pagliarini
Chromosome number; Meiosis; Mesosetum chaseae; Microgametogenesis; Pollen viability; ‘Grama-do-cerrado’

The genus Mesosetum is a primarily South American genus with 42 species. Mesosetum chaseae, regionally known as ‘grama-do-cerrado’, is abundant in the Pantanal Matogrossense (Brazil); it is a valuable resource for livestock and for environmental conservation. We collected specimens from the Nhecolandia sub-region of the Brazilian Pantanal, located in Corumbá, Mato Grosso ... more

L.A.C. Silva; M.S. Pagliarini; S.A. Santos; N. Silva; V.F. Souza
Aquatic heteropteran; Meiosis; NOR; Spermiogenesis; Vesicle

We examined the course of spermatogenesis and the meiotic chromosome complements in aquatic species of true bugs, Heteroptera. The chromosome complement of the Veliidae species was 2n = 39 (38A + X0) and 23 (22A + X0) in Rhagovelia whitei and Rhagovelia sp, respectively, and in the species of the Notonectidae (Martarega sp) it was 26 (22A + 2m + XY); all ... more

M.M.U. Castanhole; L.L.V. Pereira; H.V. de Souza; M.M. Itoyama
Cytomixis; Houttuynia cordata; Meiosis; Microsporogenesis; Polyploidy

Houttuynia cordata (Saururaceae) is a leaf vegetable and a medicinal herb througout much of Asia. Cytomixis and meiotic abnormalities during microsporogenesis were found in two populations of H. cordata with different ploidy levels (2n = 38, 96). Cytomixis occurred in pollen mother cells during meiosis at high frequencies and with variable degrees of chromatin/ ... more

J.Z. Guan; J.J. Wang; Z.H. Cheng; Y. Liu; Z.Y. Li
Cytomixis; Meiosis; Microsporogenesis; Pinellia ternata; Polyploidy

Pinellia ternata is an important traditional Chinese medicinal plant. Its different populations in China have various ploidy levels, based on x = 13, as well as extensive aneuploid series. The microsporogenesis process was observed in specimens from three populations from three regions of Hubei Province; they were characterized by normal and abnormal meiotic divisions in ... more

Y. Liu; R.K. Hui; R.N. Deng; J.J. Wang; M. Wang; Z.Y. Li
Hexaploidy; Interspecific hybridization; Meiosis; Poaceae; Polyploidy

Cytological investigation revealed complete asynapsis during microsporogenesis in 2 wild accessions of Paspalum jesuiticum collected in distinct Brazilian regions. Both accessions were hexaploid (2n = 6x = 60) and 60 univalents could be counted at diakinesis. In this phase, the majority of meiocytes exhibited univalents with both chromatids. After alignment at the metaphase plate ... more

R.A.Bernardo Filho; A.C.C. Santos; F.H.D. Souza; J.F.M. Valls; M.S. Pagliarini