Abstract: A comparative study of meiosis of pollen mother cells in Manglietia patungensis Hu and its closely related species M. yuyuanensis Law was carried out. These two species had the same chromosome number of 2n=38 and the same karyotype, but their chromosomal behaviors in meiosis were different. In M. patungensis, the typical chromosome configurations observed at metaphase were 2n=0.30IV+18.33II+0.15I, whereas those in M. yuyuanensis were 2n=19II, indicating that some chromosomes in M. patungensis might have undergone inversion and that some chromosome components were possibly paracentric inversion heterozygotes. The abnormal rate of chromosomal behaviors at anaphase I and II was different in the two species. At anaphase II, 8.8% cells were observed with lagging chromosomes which in each cell did not exceed two in M. yuyuanensis, but in M. patungensis, 29.2% cells were observed with lagging chromosomes which could reach 11 in each cell. Additionally, broken chromosomes were observed in M. patungensis. The above results indicate that the abnormal rate of chromosomal behaviors in the meiosis of M. patungensis was higher than that in M. yuyuanensis. The abnormal behaviors of the chromosomes in meiosis observed in M. patungensis may have affected the development of pollen grains in this species.

Key words: Manglietia patungensis, Manglietia yuyuanensis, endangered species, meiosis.