用荧光原位杂交技术对45S和5SrDNA在大麦(HordeumvulgareL.)有丝分裂中期染色体进行了确定分析,较强的45SrDNA信号共有2对,分别分布在大麦的第1染色体的短臂和第2染色体的长臂。而5SrDNA则只有1对杂交信号,位于第3染色体的长臂,但信号较弱。用伸展DNA纤维的荧光原位杂交(Fiber-FISH)技术测定了5SrDNA在大麦的基因组中的拷贝数,计算出5SrDNA的拷贝数约为408～416。对大麦品种中rDNA位点数目的可变性进行了讨论。 Two pairs of 45S and 5S rDNA metaphase chromosomes of Hordeum vulgare L. were identified by fluorescence in situ hybridization. Two strong 45S rDNA signals were located in the short arm and chromosome 2 of chromosome 1 arm. While 5SrDNA has only one pair of hybridization signals, located on the long arm of chromosome 3, but the signal is weak. The copy number of 5SrDNA in the genome of barley was determined by using Fiber-FISH technique with stretched DNA fibers. The copy number of 5SrDNA was calculated to be about 408 ~ 416. The variability of the number of rDNA sites in barley cultivars was discussed.