Understanding germination requirements of native species is an important component of restoration in south Puget Lowland prairies (Washington, USA). We conducted an experiment to determine the effects of pre-germination treatment and germination temperature conditions on the proportional germination of three species of Lupinus. For one species, Lupinus lepidus, germination was highest following heat shock treatments to the dormant seed, suggesting adaptation to the high temperatures associated with wildfire. For a more widespread species, Lupinus polyphyllus, high heat treatments had no effect, and germination was mildly higher in a temperature sequence simulating winter chilling followed by cool, diurnally alternating temperatures. For a final intermediate species, Lupinus albicaulis, responses to germination temperatures were dependent on high-heat treatments. These data suggest interspecific variation in germination cues where these Lupinus species are influenced differentially by environmental conditions in both breaking of physical dormancy and the promotion of germination. Our results have the potential to improve the establishment of these species from seed in restoration. Specifically, there may be implications for the timing of manual seed sowing and the efficacy of seed establishment following exposure to fire in south Puget Lowland prairies.
For more articles from the Spring 2011 issue of Northwest Science please refer to the link below: