ABSTRACT
Seeds of common Kentucky bluegrass (Poa pratensis L.) soaked for 4 days at 20°c in water had faster germination than untreated seeds provided the hydrated seeds were not dried before planting. Drying these hydrated seeds greatly decreased percentage germination. Seeds primed (−1.5 MPa, 4 days, 20°c) matrically in fine vermiculite or osmotically in KNO3 or polyethylene glycol 8000 (PEG) had faster germination than untreated seeds at 15 °C, but synchrony and percentage of germination was not increased. Drying of the primed seeds delayed germination slightly but had no effect on percentage emergence. For seeds primed then dried before sowing, matric priming (−1.5MPa, 4 days, 20QC) led to faster germination than osmotic priming. Soaking or matric priming seeds for 8 days at 5°c resulted in similar germination advancement at 10°c or 30°c, but the advancement was not as great as that achieved with 4 day matric priming at 20°c. The most beneficial presowing treatment was matric priming for 4 days at 20°c for it resulted in faster germination than osmotic priming or seed soaking treatments; a response that was more pronounced at 10°c than 30°c. In a greenhouse experiment (17713°c, day/night, sufficient seedbed moisture), matric primed seeds (-1.5 MPa, 4 days, 20°c) advanced seedling emergence, increased percentage emergence and increased seedling shoot dry weights compared to untreated seeds. This increased seedling growth was associated with earlier germination and not to increased growth rate.