Evolutionary processes in aquatic plant populations

摘要: Abstract Aquatic plants exhibit striking taxonomic, morphological and ecological diversity. This variation limits the ability to pose general hypotheses with regards evolutionary processes in aquatic plants. Here we ask whether population structure, reproductive systems, gene flow patterns of genetic differentiation are likely differ any significant way from terrestrial Defining plant populations is best attempted using demographic techniques for estimating effective size (Ne. Data available species suggest that Ne many annual aquatics be small, a fraction census number. In highly clonal species, especially those water-dispersed vegetative fragments, sizes may widely related taxa. However, measuring such will probably require approaches more similar used study vagile parthenogenetic animals than populations. Reproductive systems plants, though well described, have only begun receive quantitative study. Levels inbreeding other mating-system parameters been measured several emergent but lacking floating-leaved, submerged or free-floating Extensive propagation presents analytical difficulties also provides experimental opportunities studying variation, particularly relationship between large clone self-fertilization. Limited sexual reproduction has observed clonal, species; there little attempt, however, investigate extent which sterility can attributed environmental factors, explore accumulates lineages. Gene greatly affected by discrete patchy nature habitats directional transport propagules running waters. While movement influenced habitat consequences local long-distance dispersal depend on type propagule involved. Transport fragments lead frequently successful establishment seed, may, part, explain extensive geographical ranges species. A survey electrophoretic 81 taxa revealed distribution diversity within among as their counterparts, appears determined primarily breeding life histories. contrast, data groups widespread monomorphism. The data, limited, making interpretation this pattern difficult, cases where uniformity at isozyme loci associated physiological differentiation. Further microevolutionary studies help clarify apparent conservative macroevolutionary exhibited certain families.