兜兰亚属12种植物的核型分析

Karyotypes of 12 Species of Paphiopedilum subgenus Paphiopedilum

对兜兰亚属(Paphiopedilum subgenus Paphiopedilum)12种植物的染色体数目和核型进行了研究。结果表明:这12种植物的染色体数目和核型存在差异,其中菲律宾兜兰(P.philippinense)的核型公式为2n=2x=26=16m+10sm,长瓣兜兰(P.dithanum)为2n=2x=26=20m+6sm,密毛兜兰(P.densissimum)为2n=2x=26=22m+4sm,飘带兜兰(P.parishii)和带叶兜兰(P.hirsutissimum)为2n=2x=26=24m+2sm,亨利兜兰(P.henryanum)、虎斑兜兰(P.markianum)和根茎兜兰(P.rhizomatosum)为2n=2x=26=26m,而胼胝兜兰(P.callosum)为2n=2x=32=2M+24m+6sm,布玲兜兰(P.microchilum)为2n=2x=38=28m+10sm,卷萼兜兰(P.appletonianum)和海南兜兰(P.hainanensis)为2n=2x=38=30m+8sm。兜兰亚属的染色体主要为中部着丝粒染色体,未见随体;最长染色体与最短染色体之比为2.07～3.44,臂比大于2的染色体比率为0～0.231,核不对称系数为53.50%～58.95%。长瓣兜兰、飘带兜兰、亨利兜兰、密毛兜兰、虎斑兜兰、带叶兜兰和根茎兜兰等6种的核型类型为1B型,其余6种为2B型。

Karyotypes of 12 species of Pqphiopedilum subgenus Paphiopedilum were studied by root tips squash method. The results showed that the chromosome number and karyotype were different among these species. Their formulae were as follows： P. philipPnense for 2n =2x =26 = 16m ＋ 10sm, P. dithceaum for 2n =2x =26 = 20m ＋6sm, P. densissimum for 2n =2x =26 =22m ＋4sm, P. p^4shii and P. hb＇sutissimum for 2n =2x =26 = 24m ＋2sm, P. henryanum, P. markicenum and P. rhizomatosum for 2n =2x =26 =26m, P. caHosum for 2n = 2x =32 =2M ＋24m ＋6sm, P. microchilum for 2n =2x =38 =28m ＋ 10sm, P. qopletonicenum and P. hainanensis for 2n =2x =38 = 30m ＋ 8sm. The diploid mainly consisted of metacentric chromosomes without satellites. The ratio of the longest chromosome to the shortest chromosome （Lc/Sc） ranged from 2.07 to 3.44. The percentage of chromosomes with arm ratio （P.C.A） 〉2 ranged from 0 to 23.1%. The index of the karyotypic asymmetry （As.K） was from 53.50% to 58.95%. The karyotypes ofP. henryanum, P. dithanum, P. densissimum, P. parishii, P. markianum and P. rhizomatosum were of Stebbins＇s 1B type, and the others belong to 2B type.