Page 84 - 《广西植物》2020年第10期
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10 期            覃信梅等: 石山苣苔属四种(含一变种)植物的染色体数目和倍性研究                                          1 4 6 7


           Chromosome numbers and ploidy of four species

              (including one variety) in Petrocodon Hance


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    QIN Xinmei ꎬ PAN Bo ꎬ LU Yongbin ꎬ SHEN Lina ꎬ ZHANG Qiang ꎬ LIANG Yanni                    2∗
     ( 1. Guangxi Key Laboratory of Plant Conservation and Restoration Ecology in Karst Terrainꎬ Guangxi Institute of Botanyꎬ Guangxi Zhuang
      Autonomous Region and Chinese Academy of Sciencesꎬ Guilin 541006ꎬ Guangxiꎬ Chinaꎻ 2. Wuzhou Universityꎬ Wuzhou 543000ꎬ Guangxiꎬ
         Chinaꎻ 3. Key Laboratory of Karst Dynamicsꎬ MNRꎬ Key Laboratory of Karst Ecosystem and Treatment of Rocky Desertificationꎬ
               MNRꎬ Institute of Karst Geologyꎬ Chinese Academy of Geological Sciencesꎬ Guilin 541004ꎬ Guangxiꎬ China )

       Abstract: Petrocodon Hance (Gesneriaceae) consists of 41 species and is mainly distributed in the limestone region of
       South China. So farꎬ the chromosome numbers of only four species have been reportedꎬ with the rest species in the genus
       remained uninvestigated yet. Furthermoreꎬ the evolutionary history of the chromosome number and ploidy in Petrocodon

       as well as in its sister genus Primulina remain unexploredꎬ and particularly whether it affected their diversifications into
       extant species diversity remain unknown. In this studyꎬ the root tip cells of four species (including one variety) of
       Petrocodon (i.e. Petrocodon dealbatus var. dealbatusꎬ Petrocodon dealbatus var. denticulatusꎬ Petrocodon longangensis

       and Petrocodon sp.) which were generated by hydroponic culture method for the cutting leavesꎬ were used for the
       chromosome experiments. Firstꎬ the effects of various experimental treating conditions on the quality of chromosome
       squashing were explored and the chromosome numbers were counted. Thenꎬ the evolutionary history of chromosome
       numbers in Petrocodon and Primulina were traced based on the molecular phylogenetic treeꎬ and whether the
       diversifications of the species diversity for the two genera were impacted by changes of the chromosome number or
       especially the ploidy or not was discussed. The results were as follows: ( 1) The root tip of 1 - 1. 5 cm lengthꎬ
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       pretreatment for 5 h with 0. 002 mol  L  8 ̄hydroxyquinoline solution and dissociation for 4 min was a suitable
       chromosome preparation condition. (2) All the four species (including one variety) investigated were diploid and the
       chromosome numbers were the same (2n = 2x = 36). (3) Although the reconstruction of the ancestral state of the
       chromosome number of Petrocodon and Primulina failed to give any resolution for the most recent common ancestors of
       the two genera ( generic stem node) and each of the genera ( generic crown nodes)ꎬ the chromosome number of
       Petrocodon and Primulina was highly conserved with most taxa possessing 2n = 2x = 36ꎬ except for the ploidy or
       chromosome number changes in few speciesꎬ suggesting the disproportional diversification of species diversity between
       Petrocodon and Primulina was not correlated to the change of the chromosome number or ploidy. This study provides a
       reference for the chromosome preparation of Petrocodon and its alliesꎬ and also provides basic data and implications for
       further research on the classificationꎬ systematic evolution and speciation of Petrocodon.
       Key words: Petrocodonꎬ chromosome numbersꎬ genome ploidyꎬ species diversification

       石山苣苔属( Petrocodon Hance) 于 1883 年建            修订:原石山苣苔属(Petrocodon Hance)、朱红苣苔
   立ꎬ隶 属 于 苦 苣 苔 科 ( Gesneriaceae) 长 蒴 苣 苔 族         属 ( Calcareoboea Wu ex Li )、 方 鼎 苣 苔 属
   (Trib. Didymocarpeae Endl.)ꎮ 该属早期仅包含 1 种          (Paralagarosolen Wei)、世纬苣苔属(Tengia Chun)、

   和 1 变种ꎬ即石山苣苔(Petrocodon dealbatus)和齿缘             长檐苣苔属(Dolicholoma Fang & Wang)和细筒苣苔
   石山 苣 苔 ( Petrocodon dealbatus var. denticulatus)  属(Lagarosolen Wang) 的所有种ꎬ以及长蒴苣苔属
   (Wang et al.ꎬ1998ꎻ李振宇和王印政ꎬ2005ꎻ韦毅刚                ( Didymocarpus Wallich ) [ 柔 毛 长 蒴 苣 苔 ( D.
   等ꎬ2010)ꎮ 近年来ꎬ通过分子系统发育研究ꎬ结合                        mollifolius)、绵毛长蒴苣苔(D. niveolanosus) 和东南
   进一步的形态特征比较ꎬ对石山苣苔属进行了分类                            长蒴苣苔 ( D. hancei)]、 文采苣苔属 ( Wentsaiboea
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