Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 3, 2005
Publication Date: N/A
Interpretive Summary: Narrow-leafed milkweed (Asclepias fascicularis) is a native perennial species that is widely found throughout the Intermountain and coastal areas of the far western United States. Narrow-leafed milkweed is highly toxic and therefore of concern to resource managers. Germination profiles were conducted on this species to better understand the seed and seedbed ecology of this species. Along with testing germination at 55 constant or alternating temperatures, enrichment with gibberellin was tested, as was potassium nitrate.
Technical Abstract: Narrow-leafed milkweed (Asclepias fascicularis) is a perennial herbaceous species native to a wide area in the coastal and intermountain far western United States. This plant is of interest to resource managers because it is highly toxic when grazed in a field or consumed in contaminated hay. Toward eventual understanding of the seed and seedbed ecology of this species our purpose was to investigate seed germination at a wide range of temperatures, 0-40°C and 50°C. We also investigated the germination with enrichment of gibberellin as well as the enrichment with potassium nitrate. Narrow-leafed milkweed had no germination if the cold temperature was 15°C or lower. Optimum germination occurred at some temperature regimes in the range of 35 and 40°C, no germination occurred at 50°C. There was a significant increase in germination when enriched by both gibberellin and potassium nitrate.