| Abstract: | Patterns of phenotypic and genotypic variability in two populations of the moss, Funaria hygrometrica, were investigated using measurements of gametophytic and sporophytic morphology, sporophytic reproductive output, spore germination, gametophytic growth rates and tolerances of copper, cadmium, and low nutrient conditions, and electrophoretically detectable enzyme variation. The two populations differed in all traits measured, but complete monomorphism within populations at 14 enzyme loci suggested that each represented a single clone. Variability in gametophytic growth rates and responses to different experimental media, however, occurred among haploid sib families (families of meiotic progeny derived from the same sporophyte) and among sibs within families within both populations, suggesting high levels of genetic variability. Low mean reproductive output and a high level of variability among sporophytes in a mine site population probably reflected heavy metal toxicity. Based on this study, in combination with previous work on F. hygrometrica (Shaw, 19906), somatic mutation and/or nongenetic effects appear to contribute significantly to phenotypic variability in natural populations. |
