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以番茄的45SrDNA为探针,采用荧光原位杂交(fluorescence in situ hybridization,FISH)技术与核型分析相结合的方法,对益母草(Leonurus japonicus Houtt)的核型和45S rDNA在染色体上的定位进行了研究,同时采用压片法观察了其花粉母细胞减数分裂中染色体的行为。结果表明,益母草绝大多数花粉母细胞减数分裂中染色体的行为正常,终变期形成10个二价体,佐证了益母草的染色体数目为2n=20,且为二倍体,其减数分裂为同时型,花粉粒育性为97.10%。益母草体细胞有丝分裂中期染色体上具有2对45S rDNA杂交信号,分别位于第2号染色体短臂的末端和第3号染色体短臂近着丝粒处,益母草的核型公式为2n=2x=20=2m+16sm(2SAT)+2st,染色体相对长度组成为2n=2L+8M2+10M1,最长染色体与最短染色体的比值为1.58,核型不对称系数为69.39,染色体相对长度变异范围为8.05%～12.73%,其核型为“3A”型。基于上述结果绘制了益母草的核型模式图。
Using the 45S rDNA of tomato as a probe, the karyotype of Leonurus japonicus Houtt and the localization of 45S rDNA on the chromosome were analyzed by fluorescence in situ hybridization (FISH) and karyotype analysis The study, at the same time using the tabletting method observed chromosome pollen mother cell meiosis behavior. The results showed that most of the pollen mother cells in meiosis chromosome normal behavior, the final phase of the formation of 10 bivalents, evidence that Leonurus grass chromosome number 2n = 20, and diploid, its meiosis For the same type, pollen grain fertility was 97.10%. There are two pairs of 45S rDNA hybridization signals in the mitotic metaphase chromosome of Motherwort, located at the short arm of chromosome 2 and near the short arm of chromosome 3, respectively. The karyotype of Leonurus was 2n = 2x = 20 = 2m + 16sm (2SAT) + 2st, the relative length of the chromosome is 2n = 2L + 8M2 + 10M1, the ratio of the longest chromosome to the shortest chromosome is 1.58, the asymmetry coefficient of the karyotype is 69.39, and the relative length variation range of the chromosome is 8.05% 12.73%, its karyotype is “3A” type. Based on the above results, the karyotype diagram of Leonurus was drawn.