同源四倍体青花菜花粉母细胞的减数分裂

Meiosis of Pollen Mother Cells in Autotetraploid Broccoli

以同源四倍体青花菜为材料,采用常规压片法研究花粉母细胞减数分裂行为。结果表明:同源四倍体青花菜花粉母细胞减数分裂过程与二倍体基本相同但有其特殊性。主要表现在:中期Ⅰ染色体的构型复杂,有多价体、四价体、三价体、二价体和单价体;中期Ⅰ和中期Ⅱ有赤道板外染色体;后期Ⅰ和后期Ⅱ出现落后染色体、染色体桥及断片;后期Ⅱ和末期Ⅱ还出现染色体分离不同步及不等分裂的现象;四分体时期出现二分体、三分体、含微核的异常四分体及多分体。花粉母细胞减数分裂平均异常频率为31.5%,是同源四倍体青花菜花粉育性低的细胞学原因。

Cytological studies were conducted on pollen mother cells （PMCs） meiosis of autotetraploid broccoli using chromosome preparation technique. Results showed that the PMCs meiosis of the autotetraploid was similar to the diploid. However, there were particularities： in metaphase, multivalent, quadrivalent, trivalent, bivalent and univalent were observed. Some of the chromosomes were found not to rank at metaphase plate in metaphase Ⅰ and metaphase Ⅱ cells. In anaphase Ⅰ and anaphase Ⅱ, there were lagged chromosomes, chromosome bridges and fragments. During anaphase Ⅱ and telophase Ⅱ chromosome segregations were not synchronous and equal. At tetrad stage, dyad, triad, tetrad with micronucleus and polyad appeared. The emergence frequency of abnormal phenomena in each stage of meiosis was counted and it was 31.5% in autotetraploid. Abnormal meiosis of PMCs was the cytogenetic reason for fertility reduction of autotetraploid broccoli pollen. B