微型水仙染色体C—带带型研究

The Giemsa C_banding Patterns of Mini_daffodil (Narcissus bulbocodium)Chromosomes

用引自日本的微型水仙进行了ＣｉｅｍｓａＣ＿带带型分析，发现其４２条染色体均显带，其中除１条长染色体只在长臂上显示端带外，其余４１条染色体两臂均显端带；５条长染色体除具两个端带外，还在长臂上显出一个近端带，其中１条长染色体除显示上述带型外，还在长臂上多显示一个中间带；６条短染色体除两臂均显端带外，还显示有着丝粒带。从带型的多型性判断，该水仙可能是一个在进化过程中曾发生过染色体结构变异、基数为７的六倍体；根据中国水仙染色体显带者较少，且基数主要为１０推断，它和微型水仙的亲缘关系较远；也表明，Ｃ—带分析技术在水仙染色体组型分析、分类及起源研究中可提供有用信息。

Root tip chromosomes of mini_daffodil ( Narcissus bulbocodium L., 2n=42) introduced from Japan were C_banded with Fisher Giemsa. It was found that except 1 chromosome with only 1 terminal band on the long arm all 41 chromosomes showed sharp telomeric bands on both arms. The banding pattern of the putative homologues appeared to be basically similar, and slight divergency was also observed individually. Among the 42 chromosomes 6 short chromosomes with centromeric bands and 5 long ones with subterminal bands on the long arm were also found. And one of above mentioned 5 long chromosomes showed another interstitial band additionally. On the basis of C_banding patterns, mini_daffodil should be a hexaploid with 2n=6x=42. And some of its chromosomes probably had occured structural change as a result of long term vegetative propagation. The relation between 6x mini_daffodil and Chinese narcissus ( N. tazetta L., 2n=3x=30) seemed to be fairly distant. In addition, this study also showed that the Gimesa C_banding technique could be used as an effective method for cytogenetical research on the origin and evolution of the genus of Narcissus.