同源四倍体青花菜的核型分析

以四倍体青花菜为材料,采用常规压片法进行核型分析和有丝分裂观察.结果表明:四倍体青花菜核型公式为2n=4x=36=16m+20sm(4 SAT),其中第3、4、7、8对为中着丝粒染色体,第1、2、5、6、9对为近中着丝粒染色体,第6对染色体具随体;核型类型属于2A型,为基本对称型;染色体相对长度组成为2n=36=16 M_2+20 M_1,表明该四倍体青花菜是二倍体加倍得到,为同源四倍体.在部分四倍体根尖中发现非整倍体细胞,其染色体数目变异较大;与二倍体相比,四倍体有丝分裂过程存在双核仁、体细胞配对、染色体桥等异常现象.

Karyotype Analysis of Autotetraploid Broccoli

The autotetraploid broccoli were used to made karotype and mitosis studies by conventional pressed slice method.The results revealed the karyotype formula of autotetraploid broccoli:2n=4x=36=16m+20sm (2SAT),which had 4 pairs of metacentric chromosomes (3,4,7,8) and 5 pairs of acrocentric chromosomes (1,2,5,6,9).Satellites was observed at the sixth pair of chromosomes.The karyotype type belonged to 2A,presenting an ultimately symmetry karyotype.The consist of the relative length about autotetraploid broccoli was 2n=36=16 M_2+20 M_1.All of above were proved that autotetraploid broccoli was obtained by diploid's doubling.Besides this,aneuploid cells in some autotetraploid broccoli roots were found,in which the chromosome number had a greatly variation range.Compared to diploid mitosis process,the study observed abnormal phenomena including amphinucleolus,somatic chromosome pairing,chromosome bridges.