Voortplanting en zaadverspreiding bij Kleine egelskop (Sparganium emersum Rehmann, Sparganiaceae)

Rivers offer special environments to aquatic plants because of (1) the continuous subjection to turbulent flow, (2) the unidirectional nature of the water flow and (3) the one-dimensional, linear arrangement of populations along the river course. Here we will discuss the consequences of these characteristics for the reproductive strategy and dispersal of the 1-seeded fruits of Unbranched bur-reed (Sparganium emersum) in river systems. Subjection to turbulent flow may damage the leaves and root systems of plants. Aquatic plants can avoid such damage by adjusting their morphology in such a way that their hydraulic resistance is reduced. However, these morphological adaptations may have negative consequences for their ability to reproduce sexually, and subsequently for their genotypic diversity within populations. In the first part of this article we will describe the relationships between water velocity and plant morphology, sexual versus clonal reproduction, and the genotypic diversity within populations for Unbranched bur-reed (5. emersum). Most aquatic plants lead a sessile life style and depend on free-floating diasporas (such as seeds, fruits, and vegetative plant fragments) for their dispersal. In the second part of this article we will discuss dispersal of seeds and fruits by different vectors (water, fish, waterfowl). Here we will particularly focus on how differences in seed and fruit characteristics and vector characteristics affect the dispersal of seeds and fruits