Novel polymorphic microsatellite loci isolated from the yellow waterlily, Nuphar lutea

Riverine habitats provide unique opportunities to study the effects of gene flow on the genetic structure of populations of aquatic macrophytes. Seeds and vegetative parts (like rhizomes and turions) are often hydrochorically transported, and it is, therefore, likely that they disperse exclusively in the downstream direction. Because of the difference in physical properties, seeds and vegetative parts will have different dispersal ranges ( Johansson & Nilsson 1993). In contrast, pollen dispersal will be multidirectional as it occurs usually via insects. Gaining insight toward the biological transport function of rivers involves assessing the dispersal behaviour of the various dispersal agents, estimating the contribution of seed and vegetative dispersal compared with pollen dispersal and investigating the allocation to sexual and asexual reproduction in local populations ( Ouborg et al. 1999 ).