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异叶苣苔属(苦苣苔科)的核型研究

王印政, 顾志建, 洪德元   

  • 收稿日期:1900-01-01 修回日期:1900-01-01 出版日期:1998-01-10 发布日期:1998-01-10
  • 通讯作者: 王印政

Karyotypes of Whytockia (Gesneriaceae)

WANG Yin-Zheng, GU Zhi-Jian, HONG De-Yuan   

  • Received:1900-01-01 Revised:1900-01-01 Online:1998-01-10 Published:1998-01-10
  • Contact: WANG Yin-Zheng

摘要:

本文首次报道了中国特有异叶苣苔属的染色体数目及核型。该属所研究种类的染色体数目均为
  2n=18,染色体长度在2.0µm以上,在尖舌苣苔族所报道的染色体中显示出较原始的性状。尖舌苣苔
  族的染色体基数可能是x=9。异叶苣苔属的间期核均为复杂型;前期染色体呈渐变型。核型从对称型
  向不对称型的演化主要表现在近中部着丝粒,尤其是近端部着丝粒染色体比例的增大。毕节异叶苣苔
  W.bljieensis和峨眉异叶苣苔W.tsiangiana var.wilsonii的核型分别为2n=2m+8m+8sm(1sat)和
  2n=2m+8m(1sat)+8sm(2sat),较为对称。紫红异叶苣苔W.purpurascens和白花异叶苣苔W.
  tsiangiana var. tsiangiana的核型分别为2n=4m+6sm+8st(1sat)和2n=4m+8sm(2sat)+6st,比较
  特化。河口异叶苣苔W.hekouensis的核型是2n=4m+10sm(1sat)+4st,处于二者之间。峨眉异叶苣
  苔和原变种白花异叶苣苔的核型差异较大,在外部形态方面二者之间的性状变异也间断较大。本文建
  议将该变种从白花异叶苣苔W.tsiangiana中移出自成一种,并和毕节异叶苣苔近缘。

关键词: 非对称, 染色体基数, 进化, 核型, 异叶苣苔属, 尖舌苣苔族

Abstract:

 The karyotypes of the genus Whytockia was investigated in order to reveal its sys-
 tematic position in the tribe Klugieae and the evolution of karyotypes within this genus. The
 chromosome numbers are 2n=18 with their length over 2.0 µm in all the investigated
 species of Whytockia,  which represents the most primitive characteristics in the tribe
 Klugieae. This paper suggests that x=9 be the primitive basic number of chromosomes in
 the Klugieae. The morphology of the resting nuclei in Whytockia belongs to the complex
 chromocenter type. The chromosomes at mitotic prophase are classified into the gradient
 type. The evolution of karyotypes in Whytockia is toward increase of the chromosomes with
 submedian centromeres and especially those with subterminal centromeres. The karyotype of
 the variety W. tsiangiana (Hand.-Mazz.)A. Weber var. wilsonii A. Weber is distinctly
 different from that of W. tsiangiana var. tsiangiana, which conforms well with the gross
 morphology. This paper suggests that this variety be separated from W. tsiangiana as an
 independent species with affinity to W. bijieensis.

Key words: Asymmetry, Basic number, Evolution, Karyotype, Whytockia W. W. Smith