• Dow, Melissa A.
  University of Maine Graduate School
  

Germination ecophysiology and seed distribution were examined in seed-bank seeds of sweet-fern (Comptonia peregrina (L.) Coulter) in the laboratory and field during 1996 and 1997. Seed-bank seeds were pale beige, pitted, and had 8% viability compared to fresh-collected seeds which were glossy brown, smooth, and had 88% viability. Seeds in adjacent field and forest sites were evenly distributed throughout the study area as a whole, with similar numbers of total and viable seeds at the two sites. The depth distribution of seeds was bell-shaped with a peak at 60-80 mm below the surface at both sites. Seedlings emerged in disturbed study plots at the field site during both seasons but only during the second season at the forest site. Seasonal patterns of seedling emergence varied between the two seasons. Onset of secondary dormancy in seed-bank seeds was indicated by a sharp reduction in germination during mid-July of 1997 in the disturbed study plots and in seeds collected from the field and germinated in a   growth chamber. Seeds collected in August of 1997 and germinated in a growth chamber also showed very low germination (4.5 + 1.5%, mean + SE), but after 15 days of chilling at 4o C showed strong germination (51 + 10.6%). After chilling, August collected seed-bank seed was stimulated to germinate by temperature fluctuations of 10 C (42.0 X 0.37%), but not fluctuations of 0 C or 5o C (no germination). Nitrate was not required for seed germination, however it improved germination moderately in one experiment. Light and organic matter from the field and forest sites did not affect germination.