【摘要】 采用改良的ASG法获得了中期和 3个染色体凝缩程度不同的早中期阶段 (分别称为早中期Ⅰ、Ⅱ、Ⅲ )染色体的G_带 ,并进行了G_带核型和变动性分析。所分析的分裂时期和阶段 ,每条染色体的全长显示出了密切邻近的多重的带纹 ,带纹细窄、大小较相近 ,带间区小 ,带纹分布较密集而均匀。随着有丝分裂进程推进 ,染色体的带纹数目减少 ,早中期Ⅰ、Ⅱ、Ⅲ至中期单倍染色体组的G_带带纹总数分别减少 41 %、3 6 %、2 8%,而染色体组的绝对长度分别缩短 43 %、3 7%、2 7%,带数减少幅度与染色体长度缩短的幅度几乎相等。早中期Ⅰ至早中期Ⅱ、Ⅲ和早中期Ⅱ至早中期Ⅲ的带纹减少幅度与染色体长度缩短幅度也基本一致。染色体组中各染色体之间带纹减少和染色体缩短的比例不尽相同 ,有一定的变幅。早中期Ⅰ、Ⅱ、Ⅲ和中期染色体组中每单位绝对长度的带数 (带 /μm)分别为 2 .1 9、2 .2 2、2 .3 2和 2 .2 9,差异不大。对节节麦G_带的特性等问题进行了讨论。更多还原

【Abstract】 Clear G_bands were obtained in the mitotic chromosomes of metaphase and three prometaphases in which the chromosomes condensed differently (they were called prometaphase Ⅰ,Ⅱ,Ⅲ respectively) in Triticum tauschii (Aegilops squarrosa) by using the advanced ASG method.The G_banded karyotypes and G_band fluctuation were analyzed. The G_bands were closely adjacent, multiple and distributed all along the chromosome length in all the phases and stages. And these bands were thin,of similar size,and distributed evenly.The total number of G_bands reduced by 41%, 36% and 28% respectively, and the absolute length of chromosome complement shortened by 43%, 37% and 27% respectively, when cell mitosis proceeded from prometaphaseⅠ,Ⅱ,Ⅲ to metaphase.It was quite obvious that G_band number reduction was almost equal in extent to chromosome lenght contraction. There were differences for each chromosome in the rate of reduction of G_bands and the absolute length. Their variation ranges were also different.The band number per μm chromosome length in metaphase,prometaphaseⅠ,Ⅱ,Ⅲ were 2.19,2.22,2.32 and 2.29 respectively. It was obvious that band number per μm chromosome length of different phases and stages had little difference.The nature of G_band in T.tauschii (A.squarrosa) etc. were discussed.更多还原