H. Kudoh et Df. Whigham, A genetic analysis of hydrologically dispersed seeds of Hibiscus moscheutos (Malvaceae), AM J BOTANY, 88(4), 2001, pp. 588-593
The dispersal of floating seeds in wetland habitats should influence the ge
netic characteristics of plant metapopulations. we examined gene how of a h
ydrochorous wetland macrophyte, Hibiscus moscheutos L. (Malvaceae), by anal
yzing allozyme variation in current-year Boating-seed populations. The gene
tic composition of Rooting seeds was compared to the genetic composition of
established populations of H. moscheutos that had been previously analyzed
in the same areas. The F statistics demonstrated that genetic structuring
among floating-seed populations was weak or absent, indicating that seeds f
rom source populations were thoroughly mixed. Floating-seed populations had
an excess of homozygotes. a different situation than had previously been f
ound in established populations. The exchange of seeds was greatest among H
. moscheutos populations that were adjacent to a tidal stream. We conclude
that populations adjacent to the tidal streams are part of a metapopulation
that serves as a reserve of genetic variation in the system. Although esta
blished populations of H. moscheutos that are not close to the tidal stream
are relatively isolated genetically, we found evidence that they also cont
ribute to the floating-seed population within the estuary.