Cytokinesis

Microsporogenesis in Brachiaria dictyoneura (Fig. & De Not.) Stapf (Poaceae: Paniceae)

C. Risso-Pascotto, Pagliarini, M. S., and Valle, C. B., “Microsporogenesis in Brachiaria dictyoneura (Fig. & De Not.) Stapf (Poaceae: Paniceae)”, vol. 5, pp. 837-845, 2006.

Microsporogenesis was analyzed in five accessions of Brachiaria dictyoneura presenting x = 6 as the basic chromosome number. All accessions were tetraploid (2n = 4x = 24) with chromosome pairing in bi-, tri-, and quadrivalents. The recorded meiotic abnormalities were those typical of polyploids, including precocious chromosome migration to the poles, laggard chromosomes, and micronucleus formation. The frequency of these abnormalities, however, was lower than those reported for other polyploid accessions previously analyzed for other Brachiaria species.

Abnormal cytokinesis in microsporogenesis of Brachiaria humidicola (Poaceae: Paniceae)

E. V. Adamowski, Boldrini, K. R., Pagliarini, M. S., and Valle, C. Bdo, “Abnormal cytokinesis in microsporogenesis of Brachiaria humidicola (Poaceae: Paniceae)”, vol. 6, pp. 616-621, 2007.

Microsporogenesis was evaluated in the Brachiaria humidicola collection of the Embrapa Beef Cattle Center, represented by 60 accessions. One accession (H121) presented an abnormal pattern of cytokinesis that had never been reported in this genus. Among 900 meiocytes analyzed in the first division, 10.7% underwent precocious and multiple cytokinesis in metaphase I, fractionating the genome and the cytoplasm into two or more parts. The expected cytokinesis after telophase I did not occur.