作 者 ：ZHOU Shi-Liang
期 刊 ：植物分类学报 1999年 1期
Keywords:Mosla,
Abstract:
Seven species were recognized in Mosla in China. M. pauciflora (C. Y. Wu)
C. Y. Wu et H. W. Li is an allotetraploid (2n=36 ), while the other six species are
diploids (2n=18). Cluster analysis based on allozyme data from 28 loci of 15 enzyme sys-
tems reveals that the six diploid species formed three species pairs. M. cavaleriei Lévl.is
closely related to M. dianthera (Buch.-Ham. ex Roxb. ) Maxim., M. chinensis and M.
hangchouensis Matsuda are sibling species, and M. scabra (Thunb.) C. Y. Wu et H. W.
Li is allied to M. soochouensis. Although M. cavaleriei and M. dianthera are close rela-
tives, considerable genetic divergence has been detected between them. One third of alleles
are unique to either of them, and 28.6 % of their loci have different alleles fixed. The aver-
age genetic identity ( 1 ) between populations of these two species is 0.770, and the average
genetic distance (D) is 0.261. M. scabra and M. soochouensis are the least divergent
species pair (I =0.979, D＝0.025). No completely divergent locus was detected, and the
percentages of unique alleles are 11.1% to M. scabra and 16.7 % to M. soochouensis. This
finding indicates that a high level of genetic differentiation is unnecessarily a prerequisite of
speciation. A moderate divergence is detected between M. chinensis and M. hangchouensis
(I＝0.899, D=0.107, and 7.1% of completely diverged loci) yet the latter harbors four
times as many unique alleles (45.1% ) as the former does(11.8 % ). Compared to the genetic
divergence between M. scabra and M. soochouensis, M. dianthera and M. hangchouen-
sis and may well been undergoing active speciation have the high genetic distance between
populations (0.034 and 0.026 respectively).