Observation on meiotic behavior in three Mahonia species, with special reference to the intergeneric relationship of Mahonia and

Abstract — Cytological characters in meiosis of three Mahonia species-Mahonia fortunei, M. bealei and M. polydonta were investigated using the method of wall degradation and hypotonic treatment for chromosomal preparations. Chromosome numbers of the three species were all 2n = 2x = 28; those of M. fortunei and M. polydonta represent the first report. The three species at metaphase I possessed the same configuration of 14II, however, the secondary asso-ciation was also observed. During anaphase I, 1.5 % of the cells of M. fortunei had lagging chromosomes and chro-mosome bridges. During anaphase II, lagging chromosomes, chromosome bridges and asynchronism in second divi-sion were observed, with abnormality rate in M. fortunei being about 9.5%. The rate of fertile pollen grains of the three species amounted to more than 90%, which was consistent with the cell abnormality rate at anaphase II. The results indicate that, overall, meiotic process of the three species is normal, which is in line with the high pollen fer-tility rate and high seed yield of the three species. Our results support the view that Mahonia and Berberis represent a sister group in phylogenetic evolution, and that they should be treated as two distinct genera. Key words: abnormality rate of cells, Berberis, chromosome configuration, Mahonia, meiotic behavior, phylogeny, pollen fertility rate