三倍体狗牙根染色体数变异的分子细胞学鉴定

Molecular-cytological Identification of Triploid Bermudagrass Chromosome Number Variation

对三倍体狗牙根‘矮生百慕大’进行细胞学研究,结果表明,其细胞内染色体数存在非整倍性变异,变化范围为2n=27～30。进一步利用荧光原位杂交(FISH)技术以45S rDNA为探针进行鉴定,发现在三倍体狗牙根‘矮生百慕大’细胞中有3条染色体含有45S rDNA,并且都位于着丝粒部位。这3条染色体上的杂交信号强弱不一,两个染色体在45S rDNA区杂交信号较强,且易伸长呈线状结构,杂交信号较弱的一条染色体可能由于45SrDNA含量比较少,所以这一区域染色体很易在分裂中"拉长"并断裂,形成非整倍体。

Cytological investigation of the triploid bermudagrass showed chromosome number varies between 27 and 30 in somatic cell indicating that some of the plants were aneuploid. In order to study the chromosome variation, the digoxigenin-11-dUTP labeled 45S rDNA was used. Three distictive signals were locating to the triploid bennudagrass prometaphase chromosome centromeres by fluorescence in situ hybridization （FISH）. The intensity of three signals was different, and two signals of them showed lines sometimes. The chromosome with the weakest signal was easy to snap, and aneuploid appeared.