Pollen flow and the intrapopulation genetic structure of Heloniopsis orientalis on the forest floor as determined using microsatellite markers

Abstract 

Pollenflow, seedling dynamics, and the genetic structure of Heloniopsis orientalis (Thunb.) C. Tanaka (Liliaceae) were analyzed as part of an effort to understand the reproduction system of perennial herbs foundon the forest floor by means of microsatellite markers. It was possible to assign paternity to all offspring within this population by paternity analysis. Although no ordinary pollinator visits were observed during the flowering period, effective pollen flow occurred throughout the population. It appears that low frequencies of pollinator visits nonetheless permitted adequate pollen flow. Studies of seedling dynamics suggested restricted recruitment by means of seed. Gene flow in the present population seemed to depend mainly on pollen. Local genetic structuring caused by seeds falling near the mother plant and by vegetative reproduction was detected by means of spatial autocorrelation. Three main modes of development of genetic structure were found for this species: (1) asexual reproduction by adventitious buds, which was dominant (up to 20 cm from the parent plants); (2) sexual reproduction by seeds that fell from flower stalks (up to 60 cm from the parent plants); and (3) pollen that dispersed over a wide area (throughout the population).