濒危植物长蕊木兰的核型

Karyotypical Studies on an Endangered Species Alcimandra cathcartii (Magnoliaceae)

报道了长蕊木兰(Alcimandracathcartii)的染色体核型,核型公式为2n=2x=38=22m+15sm(3sat)+1st。核型类型属于Stebbins的2A型。第18条染色体为st染色体,第5、6、7条sm染色体的短臂上各具有1个随体。间期核为简单染色中心型(simplechromocentertype),有丝分裂前期染色体为中间型(intersti-tialtype)。对前人关于木兰属和含笑属植物的核型研究结果进行了比较分析,长蕊木兰与含笑属亲缘关系较近,但稍有区别,而与木兰属的亲缘关系较远。

The karyotype of Alcimandra cathcartii Dandy is reported for the first time. Its karyotype can be formulated as 2n = 2x= 38 = 22m ＋ 15sm （3sat） ＋ 1st, belonging to Stebbins＇s 2A type. Only the eighteenth chromosome is st chromosome, and one satellite has been found on the fifth, sixth, and seventh chromosomes respectively. The interphase nucleus is characteristic of simple chromocenter type, and during mitotic prophase, the condensation behavior of chromosomes conforms to the interstitial type. Comparing with previous karyotype research results of Magnolia and Michelia, Alcimandra cathcartii is phylogenetically closed to Michelia but far from Magnolia.