扇脉杓兰和无距虾脊兰的核型分析

Karyotype Analysis of Cypripedium japonicum Thunb. and Calanthe tsoongiana T. Tang et F. T. Wang

为了解扇脉杓兰(Cypripedium japonicumThunb.)和无距虾脊兰(Calanthe tsoongianaT.Tang et F.T.Wang)的核型,采用根尖压片法对扇脉杓兰和无距虾脊兰的染色体数目和核型进行了研究。结果表明,扇脉杓兰体细胞的染色体数为22,核型公式为2n=2x=22=16m+2sm+2st+2t,染色体相对长度组成为2n=22=2L+6M2+12M1+2S,核不对称系数为60.01%,核型分类为2B型;而无距虾脊兰体细胞的染色体数为40,核型公式为2n=2x=40=28m+10sm+2st,染色体相对长度组成为2n=40=8L+10M2+16M1+6S,核不对称系数为59.84%,核型分类为2B型;两者核型都较为对称。其中,无距虾脊兰的核型为首次报道。这为扇脉杓兰和无距虾脊兰的进化地位和种质保护提供了细胞学证据。

The aim was to understand the karyotype of Cypripediumjaponicum Thunb. and Calanthe tsoongiana T. Tang et F. T. Wang. Their chromosome number and karyotype were studied by using fingertip squashing method. The results showed that the chromosome number of Cypripedium japonium was 2n = 22, karyotype formula was 2n = 2x = 22 = 16m ＋ 2sm ＋ 2st ＋ 2t, constitution of relative length was 2n = 22 = 2L ＋ 6M2 ＋ 12M1 ＋ 2S, asymmetry index was 60.01%, karyotype type was classified as 2B; while the chromosome number of Calanthe tsoongiana was 2n = 40, karyotype formula was 2n = 2x = 40 = 28m ＋ 10sm ＋ 2st, constitution of relative length was 2n = 40 = 8L ＋ 10M2 q- 16M1 ＋ 6S, asymmetry index was 59.84%, karyotype type also belonged to 2B. Both of them have relatively symmetric karyotype. The karyotype of Calanthe tsoongiana was reported for the first time. These provided some cytological evidences for evolutionary status and germplasm conservation of Cypripedium japonicum and Calanthe tsoongiana.