山核桃花粉母细胞减数分裂及核型
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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)山核桃花粉母细胞减数分裂异常情况主要出现在中期Ⅰ及中期Ⅱ2个阶段。4)山核桃核型属于比较对称的类型,其染色体数目为2n=32,减数分裂配对成16个二价体,在倍性水平上属于二倍体。
【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 relative length was from 4. 006( ± 0. 449) to 9. 559( ±1. 175),chromosome numbers whose arm ratio was more than 2 accounted for 25. 000%,the ratio of chromosome length( L/S) and the karyotype asymmetry index were 2. 417 ± 0. 456 and 62. 875,respectively. The karyotype type was 2 B.【Conclusion】1) Although there is the phenomenon of apomixis in C. cathayensis,it still follows the law of meiosis of pollen mother cells in most angiosperms. In the whole process of meiosis,the prophase Ⅰ is the longest,other stages are short. 2) C. cathyensis pollen mother cell meiosis synchronization degree is very high,which is unfavorable to prolong its pollination period. 3) The abnormal mother cell of C. cathyensis mainly appears in the two stages of metaphase Ⅰ and metaphase Ⅱ. 4) The karyotype of C. cathyensis belongs to a symmetrical type with the chromosome number of 2 n = 32 and paired as 16 bivalents at meiosis metaphaseⅠ,thus it is a diploid species.
【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 relative length was from 4. 006( ± 0. 449) to 9. 559( ±1. 175),chromosome numbers whose arm ratio was more than 2 accounted for 25. 000%,the ratio of chromosome length( L/S) and the karyotype asymmetry index were 2. 417 ± 0. 456 and 62. 875,respectively. The karyotype type was 2 B.【Conclusion】1) Although there is the phenomenon of apomixis in C. cathayensis,it still follows the law of meiosis of pollen mother cells in most angiosperms. In the whole process of meiosis,the prophase Ⅰ is the longest,other stages are short. 2) C. cathyensis pollen mother cell meiosis synchronization degree is very high,which is unfavorable to prolong its pollination period. 3) The abnormal mother cell of C. cathyensis mainly appears in the two stages of metaphase Ⅰ and metaphase Ⅱ. 4) The karyotype of C. cathyensis belongs to a symmetrical type with the chromosome number of 2 n = 32 and paired as 16 bivalents at meiosis metaphaseⅠ,thus it is a diploid species.
引文
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高娟,伊华林,胡志勇.2010.柑橘体细胞杂种有性后代花粉母细胞减数分裂的观察.果树学报,27(1):8-12.(Gao J,Yin H L,Hu Z Y.2010.Meiotic observations on pollen mother cells of sexual progenies of citrus somatic hybrid.Journal of Fruit Science,27(1):8-12.[in Chinese])
黄有军,夏国华,王正加,等.2007.山核桃雌花发育的解剖学研究.江西农业大学学报,29(5):723-726.(Huang Y J,Xia G H,Wang Z J,et al.2007.Studies on anatomy of development of female flower in Carya cathayensis Sarg.Acta Agriculturae Universitatis Jiangxiensis,29(5):723-726.[in Chinese])
黄有军,王正加,郑炳松,等.2006.山核桃雄蕊发育的解剖学研究.浙江林学院学报,23(1):56-60.(Huang Y J,Wang Z J,Zheng B S,et al.2006.Anatomy of stamen development on Carya cathayensis.Journal of Zhejiang Forestry College,23(1):56-60.[in Chinese])
康向阳,朱之悌,张志毅.2000.毛白杨花粉母细胞减数分裂及其进程的研究.北京林业大学学报,22(6):5-7.(Kang X Y,Zhu Z T,Zhang Z Y.2000.Meiosis and its stages of pollen mother cells in Chinese white poplar.Journal of Beijing Forestry University,22(6):5-7.[in Chinese])
李懋学,陈瑞阳.1985.关于植物核型分析的标准化问题.武汉植物学研究,3(4):297-302.(Li M X,Chen R Y.1985.A suggestion on the standardization of karyotype analysis in plants.Journal of Wuhan Botanical Research,3(4):297-302.[in Chinese])
黎章矩,钱勤.1986.山核桃花芽分化与开花习性的研究.南京林业大学学报,(3):36-47.(Li Z J,Qian Q.1986.Flower bud differentiation and flowering regularity of Carya cathayensis Sarg.Journal of Nanjing Forestry University,(3):36-47.[in Chinese])
刘传虎,张秋平,姚家玲,等.2007.龙须草核型分析和花粉母细胞减数分裂的细胞学研究.中国农业科学,40(1):27-33.(Liu C H,Zhang Q P,Yao J L,et al.2007.Karyotype analysis and pollen mother cells meiosis observation in Eulaliopsis binata.Scientia Agroicultura Sinica,40(1):27-33.[in Chinese])
刘丽琴,谢江辉,李伟才,等.2011.龙眼花粉母细胞减数分裂观察.果树学报,28(5):820-824.(Liu L Q,Xie J H,Li W C,et al.2011.Meiotic observations of the pollen mother cells of Dimocarpus longan.Journal of Fruit Science,28(5):820-824.[in Chinese])
吕芳德,杨帆,张日清.2002.山核桃属部分种的核型分析.中南林学院学报,22(1):47-49.(LüF D,Yang F,Zhang R Q.2002.Karyotypes of three Carya Nutt.species.Journal of Central South Forestry University,22(1):47-49.[in Chinese])
朴锦,具红光,朴钟云.2015.关苍术花粉母细胞减数分裂及其雄配子体发育研究.西北植物学报,35(8):1547-1553.(Piao J,Ju H G,Piao Z Y.2015.Pollen mother cell meiosis and male gametophyte development of Atractylodes japonica.Acta Botanica Boreali-Occidentalia Sinica,35(8):1547-1553.[in Chinese]).
祁传磊,李开隆,肖静,等.2009.大青杨花粉母细胞减数分裂及其发育.东北林业大学学报,37(3):72-76.(Qi C L,Li K L,Xiao J,et al.2009.Meiosis of pollen mother cells and pollen development of Populus ussuriensis.Journal of Northeast Forestry University,37(3):72-76.[in Chinese])
王君,康向阳,李代丽,等.2006.通辽杨花粉母细胞减数分裂及其染色体行为研究.西北植物学报,26(11):2231-2238.(Wang J,Kang X Y,Li D L,et al.2006.Meiosis and chromosome behavior of pollen mother cell in Populus simonii Carr.×P.nigra L.‘Tongliao’.Acta Botanica Boreali-Occidentalia Sinica,26(11):2231-2238.[in Chinese])
徐进,施季森,杨立伟,等.2007.杉木花粉母细胞减数分裂的细胞学特性及异常现象的观察.林业科学,43(11):32-38.(Xu J,Shi J S,Yang L W,et al.2007.Cell biological characteristics and abnormal behavior during the meiosis of pollen mother cells in Cunninghamia lanceolata.Scientia Silvae Sinicae,43(11):32-38.[in Chinese])
许雯婷,赵健,赵楠,等.2011.欧洲黑杨花粉母细胞减数分裂观察及其不同步性分析.西北植物学报,31(10):1981-1987.(Xu W T,Zhao J,Zhao N,et al.2011.Meiosis of pollen mother cells and their asynchrony in Populus nigra L.Acta Botanica BorealiOccidentalia Sinica,31(10):1981-1987.[in Chinese])
张斌,夏国华,王正加,等.2008.山核桃开花生物学特性与雌花可授期.西南林学院学报,28(6):1-9.(Zhang B,Xia G H,Wang Z J,et al.2008.Studies on flowering biological characteristics and receptive period of female flowers of Carya cathayensis.Journal of Southwest Forestry College,28(6):1-9.[in Chinese])
张守攻,韩素英,杨文华,等.2009.红皮云杉花粉母细胞减数分裂和花粉发育的研究.园艺学报,36(7):1023-1030.(Zhang S G,Han S Y,Yang W H,et al.2009.Studies on the meiosis of pollen mother cell and pollen development of Picea koraiensis Nakai.Acta Horticulturae Sinica,36(7):1023-1030.[in Chinese])
An H Z,Hu M,Li P F,et al.2015.Chromosomal behavior during meiosis in the progeny of Triticum timopheevii×hexaploid wild oat.PLo S One,10(5):e0126398.
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