多倍体茶树的细胞学研究(一)  

Cytology Studies on the Polyploid Tea (I)

作　　者：陈士炎 叶大鹏[1] 

机构地区：[1]皖南农学院

出　　处：《茶叶科学》1989年第2期117-126,共10页Journal of Tea Science

摘　　要：对从二倍体茶树品种凤凰水仙中获得的1株高度不孕的三倍体茶树的形态特征特性、核型和减数分裂的染色体行为进行观察表明:其核型组成为2n=3x=45=36M+9SM。可区分出3个基本相同的染色体组,同源染色体组3个成员的形态极为相似。终变期观察到1—9价体、多价体环或链等构型,所有细胞可见1—12个三价体,三价体在每个细胞中平均出现次数较高,为6.13次。后期Ⅰ∶86％的细胞具有1—6条落后染色体;到达每极区染色体数变化于12—29之间,82％的细胞具有18—24条染色体。后期Ⅱ∶93％的纺锤体中具有1—4条落后染色体;到达每极区染色体数变化于8—27之间,76％的极区具有16—22条染色体,约有6％的极区具有正常15条染色体。还看到后期染色体桥。减数分裂后产生各种异常孢子并发育成各种类型和大小的花粉,其萌发率约9％。据终变期染色体构型和核型组成,初步判断这株三倍体茶树为同源三倍体。染色体数的不均衡分离,仅产生约6％具有15条染色体的正常配子,是它高度不孕的根本原因。A highly sterile triploid tea plant (Camellia sinensis), selected from a diploid tea variety (Fenghuang Shuixian), was used to study its characteristics, karyotype and meiotic chromosomal behavior. The formula of the karyotype was 2n=3x=45=36M+9SM.Fourty five chromosomes can be divided into 3 identical genomes and the shapes of the homologous chromosomes were very similar. It was observed that in diakinesis, there existed 9 forms of valents (from univalent to nine-valent), some multivalents had the shape of closed ring or open chain, the frequency of trivalents in each PMC examined ranged from 1 to 12, and the average frequency was 6.13, which was the highest among all mean frequencies of valents. In A I, the numbers of the chromosomes reached each polar region ranged from 12 to 29, 82% of the polar regions were 18 to 24. There were 1 to 6 laggards in about 86%of the PMC. In AⅡ, the numbers of the chromosomes reached each polar region ranged from 8 to 27, 76% of the polar regions were 16 to 22. There were 1 to 4 laggards in about 93% of the spindles examined, only 6% of the polar regions having 15 chromosomes were normal. In addition, the chromosome bridge can be observed in A I and AⅡ. The chromosomal synapsis and segregation of the triploid tea plant were abnormal. After meiosis, different microspores were formed and grew into the varied pollen grains. The percentage of germinative pollen was about 9%. On the basis of the genome analysis and the chromosomal configurations in diakinesis, it was regarded that the triploid tea plant may be an autotriploid. The reason of why the triploid tea plant was highly sterile was the irregularities of chromosomal behavior in the meiotic process.

关 键 词：茶树品种 落后染色体 染色体构型 多价体 凤凰水仙 染色体数 同源染色体 染色体桥 细胞学研究 三价体 

分 类 号：S571.1[农业科学—茶叶生产加工]