NÃmeros cromossÃmicos de loranthaceae e viscaceae ocorrentes no nordeste brasileiro

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

Chromosome number, interphase nuclear structure, pattern of prophase chromosome condensation and meiotic behavior were investigated in 14 Brazilian species of Loranthaceae and Viscaceae families. All species showed reticulated interphase nuclei and uniform pattern of prophase chromosome condensation. The three genere of Loranthaceae studied had 2n=16 and the three species of the single Viscaceae genus analyzed, Phoradendron, showed 2n=28. Only three species had previous karyological register, while the remainders were unknown. Analysis of the mitotic chromosome complement of two species of Phoradendron revealed a larger karyotypie asymmetry, while species of the other genera were more similar to each other and more symmetrical. The meiotic behavior in 11 species analyzed was generally regular, although some meiotic irregularities have been observed in several samples. In a single sample of Struthanthus syringifolius the occurrence of a ring tetravalent was observed in most meiocytes. These meiotic irregularities apparently did not influence the stability of chromosome numbers in both families, suggesting a structural variability higher than observed by conventional cytological techniques. These results indicate that the Brazilian populations have the same stability of chromosome numbers per genus observed in represntatives pf both families in other areas. It is suggested tha this chromosome stability is related to the high level of nuclear DNA content tipical of most of those species

ASSUNTO(S)

phthirusa psittacanthus phoradendron nÃmero cromossÃmico morfologia cromossÃmica phoradendron chromosome morphology struthanthus psittacanthus anatomia vegetal chromosome number phthirusa struthanthus

ACESSO AO ARTIGO

Documentos Relacionados