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葱属薤白的核型分化

朱世梅,许介眉   

  • 收稿日期:1900-01-01 修回日期:1900-01-01 出版日期:1999-05-10 发布日期:1999-05-10
  • 通讯作者: 朱世梅

Karyotypic differentiation in Allium macrostemon Bunge

ZHU Shi-Mei, XU Jie-Mei   

  • Received:1900-01-01 Revised:1900-01-01 Online:1999-05-10 Published:1999-05-10
  • Contact: ZHU Shi-Mei

摘要:

对薤白Allium macrostemon Bunge的13个地方居群进行了核型研究,结果表明,12个国内居群
都为四倍体,2n=4x=32;一个日本居群为五倍体,2n=5x=40。13个居群的核型类型均属Stebbins的
2A型。薤白种内存在着核型多态性。种内的核型分化与染色体的结构变异有关。主要表现为臂间倒
位、罗伯逊易位和或不等相互易位。染色体的结构变异结果导至薤白种内发生明显的核型分化。在13
个居群中,四倍体居群的核型明显可分为两类。第一类的核型公式为2n=4x=32=26m(2SAT)+6sm
(2SAT),属于该类的有华山居群、商南居群和长春居群。都江堰居群也属该类,但它的一对m随体染
色体为一对st随体染色体所代替。另一类的核型公式为2n=4x=32=24m(2SAT)+8sm(2SAT),沣峪
口居群、大飞水居群、汶川居群、武汉居群和红河居群属于该类。此外,宝兴居群、杭州居群、香山居群也
属该类,但它们各有一对染色体发生了结构变异。五倍体日本居群的核型属于第一类型,但有两条m
染色体为sm染色体所代替。最后,对薤白种内核型多态性产生的原因从环境因素,繁育制度和多倍性
3个方面进行了分析和讨论。认为不同的生境有利于诱发染色体的结构变异,兼性无融合生殖和多倍
性则有利于克服育性降低的障碍和保存在居群中所发生的染色体结构变异。通过对薤白现代分布格局
的分析,认为日本应为它的分化中心。

关键词: 葱属, 薤白, 核型, 种内分化

Abstract:

Based on a karyotypic analysis of 13 populatlons,the karyotypic differentation in
    Allium Macrostemon Bunge was investigated in this paper.The twelve populations from
    China were all found to be tetraploids with the chromosome number of 2n=32,while the re-
    maining one from Japan was a pentaploid with 2n=40.In the asymmetry,all the karyotypes
    belonged to Sebbins’2A type. Obvious karyotypic differentiation among the populations,
    which was highlighted by chromosomal aberrations,including mainly pericentric inversion
    and the Robertsonian Or unequal reciprocal translocations,was detected.Hence the kary-
    otype of this species was somewhat polymorphic.The karyotypes of the tetraploid popula-
    tions fell into two types.One was formulated as 2n=4x=32=26m(2sat)+6sm(2sat).The
    populations from Huashan,Shangnan,Changchun,and Dujiangyan had this type,though in
    the population from Dujiangyan a pair of median satellited-chromosomes was found to have
    changed into subterminal ones.The other was formulated as 2n=4x=32=24m(2sat)+8sm
    (2sat).The populations from Fengyukou,Dafeishui,Wenchuan,Wuhan,Honghe,Baox-
    ing,Hangzhou and Xiangshan all had this type,but in the three populations from Baoxing,
    Hangzhou and Xiangshan,a pair of chromosomes had undergone structural aberration.Basi-
    cally the karyotype of the pentaploid population from Japan fell into the first type,though in
    it a pair of median chromosomes had been replaced by a pair of submedian ones. Factors
    which may possibly result in the karyotypic polymorphism,including those of environmental
    conditions,breeding system and polyploidy,were analyzed.We believe that the diversified
    habitats might have induced the chromosomal structural aberratoins,and the facultative
    apomictic reproduction and polyploidy might help to surmount the obstacle of reduced fertili-
    ty and thus maintain chromosomal aberrations in populations.An analysis of the modem dis-
    tribution pattern shows that Japan may be the differentiation center of Allium macroste-
    mon.

Key words: Allium, A. macrostemon, Karyotype, Intraspecific differentiation