title: [Microsporogenesis y microgametogenesis de annatto (Bixa orellana L.)].
abstract: A series of buds of increasing maturity were individually sampled in order to examine cytological events of annatto (Bixa orellana L.), genotype Portuguesa. They were fixed in Carnoy II at 12:30 am, time of the highest rate of meiotic division. Three stain solutions were attempted. In the microspores mother cells, the use of acetic orcein 1% resulted in a good nucleus coloration and sharpness. In contrast, a well chromosome resolution was achieved with the application of propionic carmin 2%. The pollen grain mother cells (n = 8 chromosomes) at metaphase I were found in floral buds of 0.5 to 0.6 cm long; tetrad stage in buds of 0.6 to 0.7 cm long, uninucleate stage of microspores in buds of 0.7 to 0.8 cm long and the binucleate stage (pollen) in buds longer than 0.8 cm. Microphotographies showing the sequence of meiotic division (microsporogenesis) and subsequent mitosis to originate pollen grains were included.
authors.affiliation: Centro de Investigaciones en Biotecnología Agrícola (CIBA), Facultad de Agronomía, Universidad Central de Venezuela, Apartado Postal 4579, Maracay 2101, Venezuela.
authors.forename: Claret
authors.initials: C
authors.lastname: Michelangeli
authors.forename: Ada Maureen
authors.initials: AM
authors.lastname: Medina
authors.forename: Paola
authors.initials: P
authors.lastname: Artioli
authors.forename: Jonás
authors.initials: J
authors.lastname: Mata
mesh_terms: D031212:Bixaceae / Q000166:cytology / Q000235:genetics / Q000254:growth & development*; D002455:Cell Division / Q000235:genetics / Q000502:physiology; D020223:Chromosome Painting; D032461:Chromosomes, Plant / Q000502:physiology*; D011058:Pollen / Q000166:cytology / Q000254:growth & development*