| 摘要: |
| 【目的】对杉木（Cunninghamia lanceolata（Lamb.）Hook）、柳杉（Cryptomeria fortunei Hooibrenk ex Otto et Dietr）、日本柳杉（Cryptomeria japonica（Linn.f.）D.Don）、池杉（Taxodium ascendens Brongn）和落羽杉（Taxodium distichum（Linn.）Rich）染色体核型进行分析，并对它们的种间亲缘关系和进化趋势进行探讨，旨在为该科植物进化及分类提供细胞遗传学资料。【方法】采用常规压片法，运用AI细胞遗传工作系统对5种杉科植物的染色体及核型进行研究。【结果】杉木核型公式为：2n=2x=22=20m（2SAT)+2sm，核型类型属于2B型；柳杉和日本柳杉的核型公式为：2n=2x=22=20m+2sm，核型类型属于2A型；池杉和落羽杉核型公式为：2n=2x=22=22m，核型类型属于1A型。平均臂比值差异不大，为1.20～1.31；核型不对称系数变化较小，为54.24%～55.57%；最长/最短染色体值为1.36～2.18。柳杉与日本柳杉的亲缘关系较近，池杉与落羽杉的亲缘关系较近，可分为3组：杉木、柳杉和日本柳杉、池杉和落羽杉。进化顺序为杉木>柳杉>日本柳杉>池杉>落羽杉。【结论】杉科植物总体进化程度相对原始，进化速度缓慢，但种间存在广泛变异，以杉木的核型进化程度最高。 |
| 关键词: 杉科 核型分析 进化趋势 亲缘关系 四川省 |
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| Karyotypes of five Taxodiaceae species in Sichuan |
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MA Shi-yu,ZHOU Lan-ying,XIONG Hai-yan,et al
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| Abstract: |
| 【Objective】This study analyzed the karyotypes of Cunninghamia lanceolata（Lamb.） Hook）,Cryptomeria fortunei Hooibrenk ex Otto et Dietr,Cryptomeria japonica （Linn. f.） D.Don,Taxodium ascendens Brongn and Taxodium distichum（Linn.） Rich,and investigated the genetic relationship and evolution trend to provide cytogenetical information for plant evolution and classification.【Method】Traditional squashing method and cytogenetic workstation system were used to study the karyotypes of five Taxodiaceae species.【Result】The karyotype formula of Cunninghamia lanceolata（Lamb.） Hook） was:2n=2x=22=20m （2SAT)+2sm,belonging to class 2B.The karyotype formula of Cryptomeria fortunei Hooibrenk ex Otto et Dietr and Cryptomeria japonica（Linn. f.） D.Don was:2n=2x=22=20m+2sm,belonging to 2A.The karyotype formula of T.ascendens and T.distichum was:2n=2x=22=20m,belonging to 1A.Average arm ratios were 1.20-1.31 with minor differences.Karyotype asymmetry coefficients ranged from 54.24%-55.57% with small variations.The ratios of the longest chromosome to the shortest chromosome were 1.36-2.18.Taxodiaceae,C.fortunei and C. japonica were close,while Taxodium ascendens Brongn and Taxodium distichum（Linn.） Rich were close according to genetic relationship.The five species were divided into 3 categories:Cunninghamia lanceolata（Lamb.） Hook by itself,Cryptomeria fortunei Hooibrenk ex Otto et Dietr and Cryptomeria japonica （Linn.f.） D.Don,and Taxodium ascendens Brongn and Taxodium distichum（Linn.）Rich.The evolutionary tendency was in an order of Cunninghamia lanceolata（Lamb.）Hook）>Cryptomeria fortunei Hooibrenk ex Otto et Dietr>Cryptomeria japonica（Linn.f.） D.Don>Taxodium ascendens Brongn>Taxodium distichum （Linn.） Rich.【Conclusion】Taxodiaceae species were in relatively primitive evolutionary degree and the evolution was slowly.There were wide-ranging-variations between species and the karyotype of Cunninghamia lanceolata（Lamb.） Hook） had the highest evolutionary degree. |
| Key words: Taxodiaceae karyotype evolutionary trend genetic relationship Sichuan |
