花蔺和黄花蔺居群遗传结构比较研究

A COMPARATIVE STUDY ON POPULATION GENETIC STRUCTURE AND BREEDING SYSTEM BETWEEN BUTOMUS UMBELLATUS AND LIMNOCHARIS FLAVA (BUTOMACEAE)

采用垂直板型聚丙烯酰胺凝胶电泳技术 ,分别通过 1 9和 2 1个等位酶位点测定了花蔺 3个居群和黄花蔺 4个居群的遗传结构与基因流。两类群都维持较高水平的遗传多样性。花蔺居群期望杂合度、固定指数、异交率和遗传分化分别为 0 .1 44、0 .1 74、94.0 %和 0 .2 0 0 ,显示出异交繁育系统类型。黄花蔺居群期望杂合度、固定指数、异交率和遗传分化分别为0 .0 76、0 .41 5、58.5%和 0 .391 ,表明其异交 +自交的繁育系统类型。两类群的基因流分别为0 .998和 0 .390。

This study surveys genetic variations in two emergent species that differ in pollination mechanism,breeding system,and extent of sexual reproductive success.The assay of vertical slab polyacrylamide gel electrophoresis was used to quantify allozyme variability in 3 populations of the entomophilous outcrossing Butomus umbellatus L.and 4 populations of the pseudo-cleistogamy inbreeding Limnocharis flava (Linn.) Buch.based on 19 and 21 readable loci of 9 enzyme systems,respectively.Electrophoretic data showed that the populations of both species have relatively high levels of genetic diversity,low levels of genetic differentiation than other investigated aquatic taxa,quite the contrary compared with the same breeding system terrestrial taxa,probably due to isolated habitat.Population genetic diversity of B.umbellatus (A=1.35,P= 0.381,and H e=0 144) was greater than of L.flava (A=1.30,P=0.320,and H e=0.076),and population differentiation of B.umbellatus (G st =0.200) was lower than of L.flava (G st =0.391).The results were attributed to the difference in breeding systems.These data indicated that the breeding system of B.umbellatus is outcros sing (Outcrossing rate t=94.0%),yet the breeding system of L.flava is mixed selfing and outcrossing (t=58.5%) in which there seem to be a shift.The gene flow (N m) in the two species was 0.998 and 0.390,respectively.