穗花杉染色体的研究

穗花杉为国家三级重点保护的珍稀濒危植物，雌雄异株。根尖细胞染色体分析表明：雌株和雄株的染色体数目为２ｎ＝４０，其中第１对和第２对为中部着丝粒染色体，第３－２０对为端部着丝粒染色体。核型为２ｎ＝４０＝４ｍ＋３６Ｔ。雌雄株除第２对的长度稍有差异外，其余各对的相对长度和臂比都较近似，可能尚无性染色体分化。Ｇｉｅｍｓａ Ｃ带显示，间期核有３个较大的染色中心，最长的３条染色体的中央缢痕有深染色带纹，可能是着

STUDIES OF CHROMOSOMES IN AMENTOTAXUS ARGOTAENIA

Amentotaxus argotaenia (Hance) Pilger is valuable and imminent danger plant and belongs tio the prior protective plant of third class in our county. It is dioecious. Through the chromosomal analysis at the cell of root tip, it is shown as below: the chromosome number in both the female and male plants is found to be 2n = 40. Among them both third to twentieth paris of chromosome are metacentric chromosomes, the third to twentieth paris of chromosome are telochromosomes. The karyootypic formula is 2n = 40 = 4m+36T. Besides there is a little difference of the second pair of chromosome in both the female plant and male plant. The relative length and arm ratio of the other pairs of chromosome all are more approximate. It may not be differentiae in the sex chromosomes.According to the Giemsa C banding it is shown that the interphase nucleus has three bigger chromocentres. In the middle part of the three longest chromosomes there is a banding widely and darkly stained. It may be compound structure of the centromere and NOR. It is not obviously different in both the female plant and male plant.From the chromosome number and the place of satellite and secondary constriction, theAmentotaxus argotaenia all differs from other genera of Taxaceae and Cephalotaxaceae. But it is near some species of Podocarpus in the Podocarpaceae. The results made in prasent study will support Hance's concept in that the Amentotaxus argotaenia is belong to the Podocarpaceae.