| 摘要: |
| 【目的】对银腺杨大孢子母细胞减数分裂和胚囊的发育进程进行研究，为确定染色体加倍的有效处理时期提供细胞学参考，以提高通过雌配子染色体加倍途径选育三倍体的效率。【方法】2014年1月采集银腺杨雌花枝进行水培，48 h后每隔3 h采集花芽样品。采用石蜡切片法对银腺杨的大孢子母细胞减数分裂及胚囊发育进程进行研究，同步观察雌花芽的外部形态。【结果】银腺杨大孢子母细胞减数分裂及胚囊发育进程与花芽的外部形态变化存在一定的相关性，花序微露时，大孢子母细胞进入减数分裂细线期；1/2花序伸出芽鳞，发育到减数分裂中期Ⅰ；花序全部露出、长约1.55 cm左右时，进入减数分裂四分体时期。授粉前12 h，功能大孢子进入胚囊发育时期，雌蕊柱头开裂角度约180°时发育到单核胚囊；授粉后24 h，柱头褐色，发育到二核胚囊；授粉后36 h，柱头开始萎蔫，发育到四核胚囊；授粉后60 h，柱头干枯，发育到八核胚囊。【结论】根据银腺杨雌花芽外部形态可判断其大孢子母细胞减数分裂及胚囊发育时期，以适时进行染色体的加倍处理；同时，银腺杨大孢子母细胞减数分裂和胚囊发育进程呈现出明显的不同步性，同花芽的不同小花及同一小花的不同胚珠间均存在着明显的发育差异，这一特点对种群进化有重要意义。 |
| 关键词: 银腺杨 大孢子母细胞 减数分裂 胚囊发育 |
| DOI： |
| 分类号: |
| 基金项目:国家自然科学基金项目（31300562）；河北省自然科学基金项目(C2013104053)；保定学院首批科研团队（KYTD2013001）；保定市科学技术协会自然科学课题(KX2014A27) |
|
| Meiosis of megaspore mother cell and embryo sac development in Populus alba×P.glandulosa |
|
CUI Binbin,WEI Junjie,ZHANG Yan,et al
|
| Abstract: |
| 【Objective】Meiosis of megaspore mother cells and embryo sac development process of Populus alba×P.glandulosa were studied to provide cytological reference for chromosome doubling treatment and improve the efficiency of triploid breeding by female gametes chromosome doubling. 【Method】In January 2014,female flowering branches of P.alba×P.glandulosa were collected and water cultured,then flower bud were collected every 3 h after water culture 48 h.The meiosis of megasporocytes and development of embryo sacs of P.alba×P.glandulosa were studied by paraffin section method,and the flower bud morphology was observed simultaneously.【Result】The megaspore mother cell meiosis and embryo sac development were related to flower bud morphology.When a little catkin appeared,the meiosis of megaspore mother cells entered leptotene.When the meiosis of megasporocytes entered metaphase Ⅰ,1/2 catkin ran out. When the catkin was ～1.55 cm long,the meiosis of megasporocytes entered tetrad period.At 12 h before pollination,functional megaspore entered embryo sac development period.When the cracking angle of stigma was ～180 °,the embryo sac entered uni nucleate period.At 24 h after pollination,stigma was brown and the embryo sac entered two nucleate period.At 36 h after pollination,stigma began wilting and the embryo sac entered four nucleate period;while at 60 h after pollination,stigma was withered and the embryo sac entered eight nucleate period.【Conclusion】The flower bud morphology could be used to judge the megaspore mother cell meiosis and embryo sac development period,so that they could be treated by chromosome doubling technique timely.Meanwhile,meiosis stages of megaspore mother cells and development of embryo sacs presented asynchrony.There were significant development diversities in different florets of same inflorescence and different ovules in same floret,which has important significance for population evolution. |
| Key words: Populus alba×P.glandulosa megaspore mother cell meiosis development of embryo sac |
