二倍体和同源四倍体‘辣椒枣’减数分裂的比较

 观察了‘辣椒枣’（Ziziphus jujuba Mill.‘Lajiaozao’）二倍体和四倍体花粉母细胞的减数分裂过程，并将其减数分裂的各个时期加以系统分析。结果表明，与二倍体相比，同源四倍体终变期染色体构型复杂，有单价体、二价体、三价体和四价体出现，并且此时期出现双核仁，且核仁一大一小；中期Ⅰ和中期Ⅱ有部分染色体游离于赤道板外；后期Ⅰ和后期Ⅱ出现落后染色体及染色体桥现象；四分体时期还出现了二分体、含微核的异常三分体和含微核的异常四分体；减数分裂行为异常是同源四倍体‘辣椒枣’育性降低的细胞学原因。

Meiotic Observations of Pollen Mother Cells in Diploid and Autotetraploid Ziziphus jujuba Mill.'Lajiaozao'

Meiosis of pollen mother cells（PMCs）in diploid and autotetraploid‘Lajiaozao’Chinese jujube were observed，and all stages of the meiosis were analyzed. The results showed that the behavior of meiosis in autotetraploid was much more complicated than that in diploid. Compared with meiosis in diploid，the behavior of meiosis in autotetraploid was much more complicated. Diakinesis，univalents，bivalents，trivalents and quadrivalents appeared in autotetraploid‘Lajiaozao’，while two nuclei，including a large one and a small one，were observed. Some of the chromosomes were found not being arranged on equatorial plate at metaphaseⅠand metaphaseⅡfollowed by lagged chromosomes and chromosome bridges appeared at anaphaseⅠand anaphaseⅡ in the autotetraploid. At tetrad stage，dyads，triads with micronucleus，tetrads with micronucleus appeared. In conclusion，abnormal meiosis of PMCs is the cytogenetic reason for fertility reduction in autotetraploid‘Lajiaozao’.