蕹菜45SrDNA染色体定位和核型分析

Cytogenetic Location of 45S rDNA and Karyotype Analysis of Ipomoea aquatica Forsk

利用荧光原位杂交技术(FISH),定位并分析了45SrDNA在蕹菜中期染色体上的位置,其杂交信号有两个,都位于第4对染色体,一个位于着丝粒附近的长臂上,信号弱;另一个位于离着丝粒较远的长臂上,信号强。核型分析的结果显示,蕹菜的核型为:2n=2x=30=26m(4SAT)+4sm,属于1A型,染色体总长度为12.93μm。

With the help of fluorescence in situ hybridization （FISH）, we have located and analyzed the sites of the 45S rDNA on the mitotic metaphase chromosomes of I. aquatica Forsk. The results indicate that there is a pair of signs detected for 45S rDNA on the long arm of chromosome 4. One is very close to the centromere region, and relatively weak;The other sign lies in the long arm of chromosome 4 and relatively strong. The karyotype and the number of I. aquatica Forsk chromosome are also studied. The results show that the number of chromosome of I. aquatica Forsk is 2n =2x =30 =26m（4AT） ＋4sin, the total length of chromosome groups is 12.93trm, the karyotype of I. aquatica Forsk chromosome belongs to ＂1A＂ type.