水稻端四体的分子细胞学鉴定及染色体行为分析

在水稻品种中籼3037第9染色体短臂端三体的自交后代中发现了一个变异株。该植株叶片内卷,株型偏散，结实率差。分子细胞学鉴定表明，该植株体细胞染色体数比正常植株多2条，多出的染色体均比较小。进一步用来源于水稻着丝粒特异DNA序列（RCS2）以及位于水稻第9染色体短臂上的特异性DNA序列为探针，进行荧光原位杂交分析，证明该变异株多出的染色体均为第9染色体短臂，故该变异株为第9染色体短臂端四体。对变异株的减数分裂染色体行为进行分析表明，在所观察的25个细胞中，96%的细胞增加的两个端着丝粒染色体可配对形成二价体，一般不与正常的第9染色体配对形成多价体。但额外染色体形成的二价体在中期Ⅰ容易发生提前解离的现象。

Molecular-Cytological Identification and Chromosome Behavior Analysis of Telotetrasomic in Rice

From the progenies of telotrisomic chromosome 9 of an indica variety, Zhongxian 3037, a phenotypical mutant was selected. Cytological and molecular cytological investigations revealed two extra chromosomes, which were the shortest in somatic cells of the mutant. Fluorescent in situ hybridization (FISH) using a rice centromere specific DNA(RCS2) and DNA sequence specific for chromosome 9 on premetaphase and pachytene chromosomes showed that these two chromosomes were the short arms of chromosome 9. That is to say, the mutant was a telotetrasomic of chromosome 9. Among the 25 pachytene cells, two telosomic chromosomes paired each other as bivalents and didn’t pair with other normal chromosome 9 as multivalents in 96% cells. However, the bivalent was easy to disassociate in advance.