PARENT SESSION
Tuesday, August 8, 5:00-6:30 pm
Poster Session 12 - Plant population and reproductive ecology
Exhibit Hall, Ballroom Level, Cook Convention Center
Interspecific variation in seed dormancy and germination of temperate woodland herbs threatened by human harvesting.
Albrecht, Matthew1, McCarthy, Brian*,1, 1 Ohio University, Athens, OH
ABSTRACT- Seed dormancy and germination dynamics may be critical for the maintenance of temperate woodland herbs that are harvested commercially for medicinal purposes because vegetative propagules are often removed from the population, making seeds the only available link for local persistence. We used a combination of laboratory and field studies to understand how seed germination and dormancy may contribute to the population dynamics of three medicinal woodland herbs that are harvested from the wild: black cohosh (Actaea racemosa L.), bloodroot (Sanguinaria canadensis L.), and goldenseal (Hydrastis canadensis L.). In the laboratory, seeds of each species were subjected to factorial combinations of simulated seasonal temperature sequences and variation in diurnal photoperiods. Seeds of each species were also buried in seed packets in a second-growth hardwood forest and then retrieved at 90 d intervals to determine seasonal variation in dormancy, germination, and longevity. Seeds from each species were morphophysiologically dormant at the time of dispersal. Radicles emerged at great rates (> 80%) in both light and darkness when seeds for each species were moved through a summer → autumn → winter → spring simulated temperature sequence. Light was required to break cotyledon dormancy in black cohosh but not in goldenseal and bloodroot. In the burial study, a small fraction (< 15%) of bloodroot and black cohosh seeds remained dormant after a two-year period whereas no viable seeds remained in goldenseal seed packets. Interspecific variation in dormancy and germination among these co-occurring species needs to be considered when formulating plant conservation strategies.
Key words: forest herbs, nontimber forest product, regeneration dynamics, seed ecology