J Syst Evol ›› 1997, Vol. 35 ›› Issue (2): 107-116.

• Research Articles • Previous Articles     Next Articles

The Discovery of Tetraploid Camellia reticulata and Its Implication in Studies on the Origin of This Species

Gu Zhi‐jian   

  • Published:1997-03-10

Abstract: Camellia reticulata and its two allied species, C. saluenensis and C. pitardii,all from the Jinshajiang Valley of Yunnan and Sichuan, were cytologically studied in this work. Among 34 populations of C.reticulata studied here, 21 were found to be tetraploids (2n=60), 11 hexaploids (2n = 90), and the remaining two diploids (2n = 30). Tetraploid was reported in C. reticulata for the first time and its karyomophology was studied. In meiosis of pollen mother cells of the tetraploids and the hexaploids, only bivalents were observed in most of the populations, although in several populations or individuals a few univalents or tetravalents appeared. In the hexaploids, hexavalents were not observed. Thus, the meiotic chromosome cofigurations showed that the tetraploids and hexaploids in C.reticulata allopolyploids, and the appearance of a few tetravalents in some populations might indicatehomology of chromosomes in different genomes to some extent. The characteristics of the resting nuclei and the prophase chromosomes of all the tetraploids and hexaploids were quite similar to each other. The tetraploids of C.reticulata from the localities with the altitude of over 1800 m were gross-morphologically similar to the hexaploids, but those growing between 1100 ~1800 m were different to some extent from the hexaploids. In geographical distribution, the tetraploids and the hexaploids were continuous, and overlapped with C. saluenensis and C. pitardii.

Key words: Jinshajiang Valley, Camellia reticulate, Karyomorphology, Origin