茶树细胞分类学研究

本文研究了黔、滇、川、闽茶树Camellia Sinensis(L)Kuntze 9个类型的核型。染色体数目均为2n=30。9个茶树类型可分为两类：第一类包括乔木大叶类的贵州大叶茶，云南大叶茶及云南腾冲大叶茶，其核型均为”2A”型。 第二类属于灌木或小乔木类，以中小叶为主，少数为大叶的黔湄419，黔湄502雅安大叶茶，福鼎大白茶，川茶及黔湄101，核型属”2A”和”2B”，不对称性略高于第一类，为较进化的核型。从核型资料支持将茶C.sinensis分为两个亚种，同时也赞同以云贵高原为中心的茶树起源观点。

Cytotaxonomical Studies of Tea Plants

 Nine forms of Camellia sinensis (L) Kuntze from Guizhou, Yunnan, Sichuan and Fujian Provinces were cytotaxonomically studied in this work. The wall degradation hypotonic method was used for preparing chromosome samples which were stained in Giemsa. The micrographs of their somatic metaphase are shown in Plates 1-2, the ranges of chromosome relative lengths, arm ratios, karyotype  formulae  and  classification  of karyotypes  according  to  Li  and Chen (1985) are shown in Table 1 and the idiograms in Fig. l. The main points are mentioned as follows:     (1) All these forms are found to be diploid with 2n = 30, and they are reported for the first time except Yunnan(Fengqing)cultivated form.     (2) All the karyotypes of the forms examined are relatively uniform, which re- veal the gradual decrease in size from the longest to the shortest chromosomes, similar chromosomal relative length, smaller chromosome types varying between 2- 5μm. The karyotype mainly consists  of metacentric (m)  and  submeta- centric (sm) chromosomes.  Sat-chromosomes  are   difficult  to be discovered on mid -metaphase chromosomes. The cytological information confirms the close relationship among these tea forms.     (3) According to the asymmetry of karyotype, the nine tea forms are divided into two types: one consists of the arbor with macrophyll, i.e. Guizhou and Yunnan( Fengqing and Tengchong)cultivated forms,  which have the”2A” karyotype possessing metacentric(m) and submetacentric(sm) chromosomes. The karyotypes might be of the most symmetrical or primitive type ;the other consists of the bush or  microarbor with mostly medium- and microphyll, less frequently macrophyll, i.e. Qianmei 419, Qianmei 502, Yaan,Fuding, Sichuan and Qianmei 101 cultivated forms, which have the “2A” and “2B” karyotypes, consisting of metacentric (m),  submetacentric (sm)  and  a  pair  of subtelocentric  (st) chromosomes, and more asymmetrical than that of the first karyotype.  They might be more advanced.     (4) In recent years, two subspecies, i.e. ssp. “yunnan”and ssp. “bohea”, including seven varieties, in C. sinensis were recognized but not formally published by Zhuang et al. (1981). From the present work and the previous reports the au- thors agree with Zhuang’s classification, because recognition of two subspecies is re- markably consistent with the two kinds of karyotypes reported here. C.sinensis ssp. “yunnan” with arbor and macrophyll characters has more symmetrical karyotype than that of C. sinensis ssp. “bohea”  with bush or microarbor and mostly medium- and microphyll characters. That is to say, ssp.”yunnan” is more primitive than ssp. “bohea”.      (5) Based on the karyotype analysis of arbor and macrophyll teas reported before and here (see Table 3), the  authors support the viewpoint that Yunnan- Gui zhou Plateau is the original center of tea Plants, whereas Assam form in In-dia is derived.