沙田柚染色体组型及Giemsa带型分析

本文以沙田柚为材料,对其染色体组型及带型进行了观察分析。组型分析:染色体数目2n=18,根据染色体的相对长度分成大小染色体两种类型,前者包括1、2、3、4和5对,后者为6、7、8和9对,根据臂比,9对染色体能够被分成中部着丝点和近中着丝点染色体两种类型。即第5、7,9对为亚中部着丝点,其余为中部着丝点,第6对染色体上有随体;Giemsa带型:除第二对染色体只显中间带外,其余都显着丝点带,并在3、4、8对染色体短臂上和2、3、1对染色体长臂上均显端带,第2、3,6对同源染色体之间的C带显示杂合性。

AN ANALYSIS ON KARYOTYPE AND GIEMSA BANDING PATTERNS IN CHROMOSOMES OF SHATINYU HORT

Using Citurs grandis ( L. )Osbeck var, Shafinyu Hort . as experimental material, we observed and analysed their karyotype and Giemsa banding pattern of chromosomes. Following is our results.Karyotype. The number of chromosomes are 2n =18. According to their relative lengths, chromosomes can be divided into two types, large (relative length>10 ) and small ( relative length<10) . The former includes Nos. 1, 2, 3, 4, 5 pairs, the later includes Nos . 6, 7, 8,0 pairs. According to arm ratios, 9 pairs of chromosomes can be divided into designations, the submetacentric ( includes Nos. 5,7,9 ) and the metaeentrie (the others ); the 6th pair is SAT chromosome.Giemsa banding patterns : the 2th pair shows the median banding , the others show the centromeric banding. The short arras of Nos. 3, 4, 8 and the long arms of Nos. 2,3, 7 all show the end-handing, The homologous C-banding of Nos. 2, 3, 6 pairs show heterozygosity.