A cytological study of Magnolia championii Benth. (Magnoliaceae).

摘要

An analysis of the karyotype and meiotic behavior of Magnolia championii Benth. is presented. Its chromosome number is confirmed to be 2n=2x=38. The ratio of the longest chromosome to the shortest chromosome is 2.31 and the karyotype is categorized to be 2B type. The index of karyotype asymmetry is about 56.47%, which is similar to other Magnolias. The meiosis process is normal except for one or two univalent pairs caused by the advanced disjunction of few bivalents. Single chromatid bridges and double chromatid bridges are observed at meiotic metaphase I in pollen mother cells and microspore tetrads. The low ratio of the abnormality, as shown in the research, does not constitute the main cause of the aborted pollen grains.