Seeds of Lupinus perennis Wats. (perennial lupine) were subjected to a variety of scarification and temperature treatments. Without scarification, <15% germination was observed within 1 week. Germination increased quadratically as the duration of acid scarification time increased. After 15 min scarification, nearly 90% of the seeds germinated and nearly 100 percent germination was obtained after 45 min scarification. Nicking the seed coats with a razor blade resulted in 100% germination. In contrast, soaking seeds in 22C (72F) water for 24 hr failed to enhance germination. Total germination of scarified seeds was >80% between 21 and 29C (70 and 85F) within 54 hr. The most rapid germination occurred within 24 to 29C (75 to 85F). At 32C (90F), total germination was reduced to approximately 60%. At temperatures ≥ 35C (95F), total germination was reduced to less than 4%. Germination occurred equally well in the light or dark. Our data indicate that seeds of L. perennis must be scarified to germinate and the most rapid germination occurs between 24–29C (75–85F).
2Texas A&M University Research and Extension Center, 1380 A&M Circle, El Paso, TX 79927 USA.
3Texas A&M University Research and Extension Center, 17360 Coit Road, Dallas, TX 75252-6599 USA.
4USDA Forest Service, North Central Forest Experiment Station, Forestry Sciences Laboratory, Rhinelander, WI 54501 USA.