山核桃花粉母细胞减数分裂及核型  

Meiosis of Pollen Mother Cell and Karyotype of Carya cathayensis

作　　者：徐川梅 黄坚钦[2] 王正加[2] 夏国华[2] 张启香[2] 黄有军[2] 张守攻[1] Xu Chuanmei;Huang Jianqin;Wang Zhengjia;Xia Guohua;Zhang Qixiang;Huang Youjun;Zhang Shougong(State Key Laboratory of Tree Genetics and Breeding Research Institute of Forestry, Chinese Academy of Forestry Beijing 100091;State Key Laboratory of Subtropical Silviculture Zhejiang A＆F University Itangzhou 311300)

机构地区：[1]中国林业科学研究院林业研究所林木遗传育种国家重点实验室,北京100091 [2]浙江农林大学亚热带森林培育国家重点实验室,杭州311300

出　　处：《林业科学》2017年第11期77-84,共8页Scientia Silvae Sinicae

基　　金：国家高技术研究发展计划(863计划)"特色林木功能基因组研究与应用"(2013AA102605);国家自然科学基金项目(31470682);分析测试科技计划项目(2016C37081)

摘　　要：【目的】研究山核桃花粉母细胞减数分裂过程中染色体行为变化及其染色体核型特征,进而确定山核桃染色体数目及倍性水平,探索山核桃无融合生殖现象与其倍性水平的关系,丰富山核桃生殖生物学等相关研究内容,同时也为山核桃杂交育种及系统分类等研究提供一些细胞学资料。【方法】1)以山核桃雄花序为研究材料,采用DAPI荧光染色技术对山核桃花粉母细胞减数分裂过程进行研究。2)以山核桃根尖为材料,采用核型分析技术分析山核桃染色体核型。【结果】1)山核桃花粉母细胞减数分裂分2次进行。第1次为减数分裂,所形成的子细胞染色体数目减半,分为前期Ⅰ、中期Ⅰ、后期Ⅰ和末期Ⅰ4个阶段,其中前期Ⅰ最为复杂,分为细线期、偶线期、粗线期、双线期和终变期5个时期,所经历时间最长,占整个分裂周期的70%;第2次为有丝分裂,形成的子细胞染色体数目不再减半,同样分为前期Ⅱ、中期Ⅱ、后期Ⅱ和末期Ⅱ4个阶段,历时较短。2)在减数分裂同步性方面,同一小花的不同花药间及同一花序轴的不同小花间表现较为一致。3)山核桃大多数花粉母细胞减数分裂中染色体行为正常,配成16个二价体,有一定比例的异常花粉母细胞出现,主要表现为中期Ⅰ出现落后染色体,异常率为8.86%,中期Ⅱ表现为不对称分裂,异常率为15.79%。4)山核桃核型公式为2n=32=20m+12sm,染色体相对长度变化范围为4.006(±0.449)~9.559(±1.175),臂比大于2的染色体比例为25.000%,最长染色体与最短染色体之比为2.417±0.456,核型不对称系数为62.875,核型分类属于2B。【结论】1)山核桃虽然存在无融合生殖现象,但是其花粉母细胞减数分裂仍遵循大多数被子植物减数分裂规律,在整个减数分裂进程中,前期Ⅰ所需时间最长。2)山核桃花粉母细胞减数分裂同步性程度较高,不利于山核桃散粉期的延长。3)山核桃花粉�【Objective】 This study was aimed to observe the meiosis of pollen mother cell and the karyotype of Carya cathayensis,to determine the chromosome number and ploidy level of C. cathayensis according to these results,to explore the relationship between the apomixis and the ploidy level of C. cathayensis,and to enrich reproductive biology data of Carya species,meanwhile,to provide some cytological data for cross breeding and systematic classification of C.cathayensis.【Method】1） Male inflorescence of C. cathayensis was selected as material,DAPI fluorescent staining was used to study the meiosis of pollen mother cell of C. cathayensis. 2） C. cathayensis root tip was selected to prepare chromosome and make karyotype analysis.【Result】 1） The meiosis of pollen mother cells of C. cathayensis was divided into two stages,the chromosome number of daughter cells was reduced by half during the first division and not changed again during the second division. The first and second division were divided into prophase,metaphase,anaphase and telophase respectively,however,the prophase Ⅰ was most complex among these stages and was further divided intoleptotene,zygotene,pachytene,diplotene and diakinesis. The prophase Ⅰ was the longest one among these stages,accounting for nearly 70% of the whole division cycle. The second division was relatively a shorter period. 2） In terms of meiosis synchronization,different anthers from the same floret are the same,there was no significant difference among different flowers from the same inflorescence axis. 3） The chromosome behavior of most pollen mother cells in C.cathayensis was normal and paired as 16 bivalents at metaphaseⅠ. However,there was a certain proportion of abnormal pollen mother cells in the meiosis,such as appearing lagging chromosome in metaphase Ⅰ,which accounted for 8. 86%,showing asymmetry division in metaphase Ⅱ,which accounted for 15. 79%. 4） The karyotype formula of C. cathayensis was 2 n = 32 = 20 m ＋ 12 sm,and the range of its chromosome

关 键 词：山核桃 减数分裂 花粉母细胞 染色体 核型 无融合生殖 

分 类 号：S718.46[农业科学—林学]