云南大叶茶细胞学研究

本文采用去壁低渗法研究了云南大叶茶的染色体核型,间期核形态和多核现象。结果表明大多数染色体是中部着丝粒染色体,5对是近中部着丝粒染色体,第7和12对染色体中各有1条具随体染色体。根据Levan等的分类原则,其核型为2n=20m+8sm+2sm(SAT),属于Stebbins核型分类的“2A”型,同时亦发现有“2B”型的核型。云南大叶茶间期核型为浓密分散型和复杂染色中央微粒型两种;并首次发现茶树中的多核现象,在所观察的1250个细胞中有6个是具双核细胞(占0.48％),有2个是具三核细胞占(0.16％)。另外,本文还对部份山茶属植物的核型进行了讨论。从核型上可以看出:(1)山茶属植物在进化上属于较原始的种系;(2)山茶属植物核型的进化基本符合Stebbins提出的植物界核型进化的规律,即对称—→不对称;(3)山茶属植物的核型在一定范围内变异甚大,这种变异没有一定的规律性。这些观点与张宏达提出的山茶属植物的分类系统基本吻合。带随体的染色体数目在山茶属植物核型的进化上没有什么明显的变化规律。

CYTOLOGICAL STUDIES OF CAMELLIA ASSAMICACYTOLOGICAL STUDIES OF CAMELLIA ASSAMICA

In this paper,the karyotype,interphase morphokaryon and polykaryon in stem tip cells of Camellia assamica(Mast.)Chang have been studied,by wall degradation,hypotomic treatment and flame-drying method and stain with Giemsa.The somatic complement showed that the 1,2,3,6,8,9,11,13,14 and 15th chromosomes are median centromeres,the 4,5,7,10 and 12th chromosomes are submedian centromeres,and one of the 7 and 12th chromosome respective are sat-chromosome.According to the classification systems given by Levan et al.,the karyotype formulas is therefore 2n=20m+8sm+2sm(SAT).Of the 9 cells examined in this paper,6 cells are "2A" type of Stebbins karyotypic symmetry,and 3 cells are "2B" type.The interphase morphokaryon of the tea plant are complex chromocenter type and densely diffuse type.Furthermore,the polykaryon on the tea plant was observed for the first time,among 1250 cells of the tea plant was examined,6 are cells with two nuclei(0.48% two nuclei)and 2 are cells with three nuclei(0.16% three nuclei).In addition,the karyotypes of some Camellia plants were also discussed,it can be simplified as follows:(1)The genus Camellia is more original race in their evolution;(2)Karyotypic evolution of the genus Camellia basically agreeing with that concluded by Stebbins,i.e.,karyotype evolution from symmetry to asymmetry;(3)The karyotypes of the genus Camellia are obviously different to a certain degree,which is irregularity.These results basically tallied with viewpoint in "A Taxonomy of the Genus Camellia" of Chang Hung-ta.Variation of the sat-chromosome number were obviously irregularity in the karyotype evolution of the genus Camellia.In this paper,the karyotype,interphase morphokaryon and polykaryon in stem tip cells of Camellia assamica(Mast.)Chang have been studied,by wall degradation,hypotomic treatment and flame-drying method and stain with Giemsa.The somatic complement showed that the 1,2,3,6,8,9,11,13,14 and 15th chromosomes are median centromeres,the 4,5,7,10 and 12th chromosomes are submedian centromeres,and one of the 7 and 12th chromosome respective are sat-chromosome.According to the classification systems given by Levan et al.,the karyotype formulas is therefore 2n=20m+8sm+2sm(SAT).Of the 9 cells examined in this paper,6 cells are "2A" type of Stebbins karyotypic symmetry,and 3 cells are "2B" type.The interphase morphokaryon of the tea plant are complex chromocenter type and densely diffuse type.Furthermore,the polykaryon on the tea plant was observed for the first time,among 1250 cells of the tea plant was examined,6 are cells with two nuclei(0.48% two nuclei)and 2 are cells with three nuclei(0.16% three nuclei).In addition,the karyotypes of some Camellia plants were also discussed,it can be simplified as follows:(1)The genus Camellia is more original race in their evolution;(2)Karyotypic evolution of the genus Camellia basically agreeing with that concluded by Stebbins,i.e.,karyotype evolution from symmetry to asymmetry;(3)The karyotypes of the genus Camellia are obviously different to a certain degree,which is irregularity.These results basically tallied with viewpoint in "A Taxonomy of the Genus Camellia" of Chang Hung-ta.Variation of the sat-chromosome number were obviously irregularity in the karyotype evolution of the genus Camellia.