Gu Zhi-jian, Wang Li, Gong Xun, Xiao Tiao-jiang
1993, 31 (5): 399–404
Disporum cantoniense (Lour.) Merr. is widely distributed in the area
from the Himalayas to Indonesia, via south China, Indo-China and Taiwan, especially in the various parts of Yunnan Province. In this paper, the karyotype variation of six populations of the apecies from southeastern, middle and
northwestern part of Yunnan are studied. The result shows that the chromosome
number of all the populations are 2n= 14.
The species was reported to have 2n= 16, 30 (Hasegawa 1932, Mehra and
Pathamia 1960, Kurosawa 1966, 1971, Tang et al. 1984) and 2n= 14 (Kurosawa
1971, Mehra and Sachdeva 1976a). 2n= 14, 2n= 16 and 2n=32 were observed in
the material from Taiwan (Chuang, et al. 1962, Chao, 1963, Hsu, 1971, 1972,
Chang, 1974). Based on the cytological study of D. megalanthum Wang et Tang
and seven other species in this genus reported by other authors, Hong and
Zhu (1990) consider that the basic number of this genus is x= 8, because species
with 2n= 16 was more than those with 2n= 14, despite some number variation of
chromosomes in this genus. Based on the results of the present paper, we consider
that x= 7 might be one of the basic numbers of this genus.
In the karyotypes studied here, the relative chromosome lengths and the ratio
of the longest/the shortest chromosomes of the six populations are rather approximate. Moreover, all the karyotypes belong to Stebbins’3B type. However,
karyotype variation was detected in these populations. The homologues of the
2nd, 3rd and 6th pair of chromosomes are different from each other, the numbers
and popsition of satellites are found very different, among the populations except
for the Lijiang population, the 1st, 2nd, 3rd or 4th pair of all the populations exhibited heterozygosity. Although all the karyotypes belong to Stebbins ‘3B type,
the homologues were more regular in the Lijiang population than in the other
populations, and the most irregular in the Wenshan population, because it hadfour pairs of heterozygous chromosomes.