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草茨藻的多倍体系列和细胞地理学初步研究

游浚, 孙祥钟, 王徽勤   

  • 收稿日期:1900-01-01 修回日期:1900-01-01 出版日期:1991-05-10 发布日期:1991-05-10
  • 通讯作者: 游浚

A Preliminary Study on the Polyploid Series and Cytogeography of Najas graminea

You Jun, Sun Xiang-Zhong, Wang Hui-Qin   

  • Received:1900-01-01 Revised:1900-01-01 Online:1991-05-10 Published:1991-05-10
  • Contact: You Jun

摘要:

通过对草茨藻Najas graminea Del.,多倍体系列的分析,笔者认为首次发现的分布于云南的二倍体居群为偏性特有。该居群的迁移与今天草茨藻在亚洲的分布图式密切相关。该图式不表现多倍体随纬度或海拔增加而增多,也不明显与生态爱好相关。二倍体和六倍体居群核型比较以及其它证据指示草茨藻的多倍体起源可能是同源多倍化。在茨藻属中,草茨藻具最强的核型不对称性,最高的倍性和极减化的花部器官等特征,均可能指示它是该属中进化程度最高的类群。

关键词: 草茨藻, 多倍体系列, 细胞地理学, 同源多倍体, 进化

Abstract:

Najas graminea is first reported to have a population of 2n = 12. A cytogeographic
survey of this species reveals that the diploid (2n= 12) population is so far only found in
Yunnan (You Jun 8804, in Herb. WH) and its adaptive radiation has probably resulted in the
distribution pattern of N. graminea today in Asia. The polyploids are more widely distributed
than the diploid, but no correlation was found between polyploids and geographic distribu-
tion, soil or climate types. The comparison of the karyotypes between diploid and hexaploid,
lack of inter-specific hybridization in nature, and the occurrence of semi-cryptic polyploids
in the populations suggest that polyploids of N. graminea are the result of autopolyploidy (at
least in China). The highest polyploidy (almost 17X), the most asymmetrical karyotype, and
the most reduced floral structure (the spathe is absent) support the suggestion that the
N. graminea be the most advanced taxon in Najas.

Key words: Najas graminea, Polyploid series, Cytogeography, Autopolyploid, Evolution