J Syst Evol ›› 1992, Vol. 30 ›› Issue (6): 498-507.

• Research Articles • Previous Articles     Next Articles

Cytotaxonomical Studies of Tea Plants

Liang Guo-Lu, Lin Meng-Jia, Chen Jia-Yu, Liu Jun-Su   

  • Published:1992-11-10

Abstract: 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 reveal 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 submetacentric (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 authors agree with Zhuang’s classification, because recognition of two subspecies is remarkably 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 mediumand 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 YunnanGui zhou Plateau is the original center of tea Plants, whereas Assam form in In-dia is derived.

Key words: Tea, Karyotype, Evolutin, Cytotaxonomy