异叶天南星的染色体核型分析

Analysis on the Chromosome Karyotype of Arisaema heterophyllum Blume

[目的]对异叶天南星的染色体进行核型分析。[方法]以人工栽培的2年生异叶天南星种子为试材，观察种子中的中期分裂相细胞并对其进行统计和核型分析，其核型分类根据核型中染色体的长度比和臂比2项主要特征，按Stebbins的标准进行划分。[结果]异叶天南星的染色体数目为28条，组成2个染色体组。14对同源染色体中有9对是近中着丝粒染色体，5对是近端着丝粒染色体。异叶天南星的染色体核型公式为2n=28=18m＋10sm，其染色体相对长度在24．464％～63．245％的范围内，最长染色体与最短染色体的比值为2．58，臂比值大于2：1的染色体占总染色体的14．3％。异叶天南星的染色体核型为2B型，其核型不对称系数为62．83％。[结论]该研究为异叶天南星的栽培和良种选育提供了遗传学依据。

[ Objective ] The research aimed to analyze the chromosome karyotype of Arisaema heterophyllum Blume. [ Method ] With the seeds of artificially cultivated 2-year-old A. heterophyUum as tested materials, the cells in metaphase in the seeds were made for observation, statistic and karyotype analysis, and based on the 2 main features of length ratio and arm ratio of chromosome, the karyotypes were classified according to the criteria of Stebbins. [ Result]A. heterophyllum had 28 strips of chromosomes and 2 genomes were composed of them. Nine of the 14 pairs of ho- mologous chromosomes were submetacentric chromosomes and 5 of them were acrocentric chromosomes. The formula of chromosome karyotype of A. heterophyUum was 2n =28 = 18m ＋ lOsm, its chromosome relative length was in the range of 24. 464% - 63. 245%, the ratio of the longest chromosome to the shortest chromosome was 2.58 and the chromosomes with arm ratio above 2：1 accounted for 14.3% in total chromosomes. The chromosome karyotype of A. heterophyllum was Type 2B and its asymmetrical karyotype coefficient was 62.83%. [ Conclusion] The study provid- ed genetic basis for the cultivation and improved variety selection of A. heterophyllum.