Gene flow and population structure in Armeria maritima

Abstract

Gene flow distances and population structure were studied in populations of Armeria maritima (Mill). Wild, in Denmark. Gene flow was studied by direct methods using seed and pollen dispersal distances. Pollen flow in four experimental populations, where honey-bees were pollinators, surpassed the diameter of each experimental population. Seed dispersal was restricted and was used to partition a coastal grassland population into local populations. The structure of this population was analysed with a population genetic model that formulated a sequence of hypotheses about the action of natural selection and the geographical subdivision of the total population into local populations. The variation at a morphological marker locus was used for this purpose: the presence of hairs on the flower stalk in this species is determined by a dominant allele. The estimated pollen poois in the six local populations were homogeneous, and there was no evidence of deviation from random mating in any of the local populations. The genotypic distributions were homogeneous in the local populations and accorded with Hardy-Weinberg proportions. There was no evidence of selection at the studied locus, accordingly, the studied population was panmictic and its genotypic distribution could be described with a single parameter, the allele frequency at the marker locus.

Small-scale demographic compensation in a high-mountain endemic: the low edge stands still

“…Based on field observations (García-Camacho et al 2010) and results from Armeria maritima, a species with much longer flower stalks and short-distance seed dispersal (Philipp et al 1992), our matrix model assumed shortdistance seed dispersal with all seed production staying in the sampling sub-plots.…”

Ecology matters: Atlantic–Mediterranean disjunction in the sand‐dune shrub Armeria pungens (Plumbaginaceae)

“…Wind pollination has also been suggested (Woodell & Dale 1993) but it seems unlikely to be effective because of the low number of pollen grains per anther (Tauleigne‐Gomes & Lefèbvre 2005; G. Nieto Feliner, unpublished data). Parachute‐like calyces containing the fruit suggest wind dispersal although recorded distances are low in A. maritima (Philipp et al . 1992) and animal dispersal may also occur facilitated by stiff hairs of fruiting calyces.…”

Diversity and genetic differentiation among subpopulations of Gliricidia sepium revealed by PCR-based assays

“…Determinants of genetic structuring in plant populations include mating system (Loveless & Hamrick, 1984;Ranker, 1992;Carthew, 1993 and references therein), natural (and possibly artificial) selection, evolutionary history, life-history characteristics and mechanisms of gene flow (Schaal, 1980;Ellstrand et al, 1989;Hamrick & Godt, 1989;Hamrick et a!., 1992;Philipp et al, 1992). Together, these factors can lead to complex genetic structuring within populations which is often difficult to resolve.…”