Influence of scarification and temperature on seed germination of Lupinus arboreus

Seeds of Lupinus arboreus Sims (bush lupine) were subjected to a variety of scarification and temperature treatments. Without scarification, <5% germi nation was observed within one week. Germination increased linearly with in creasing treatment time in concentrated sulfuric acid up to 60 min. Beyond 60 min. there was no significant increase in germination. Nicking the seed coats with a razor blade resulted in 97% germination. Placing seeds in wate r initially at 100 degreesC and soaking the seed as the water cooled result ed in 18% germination. When seeds were soaked in lower initial temperature water treatments (60-80 degreesC), germination increased to 10% compared to 4% for the control. Total germination of scarified seeds was > 80% at germ ination temperatures between 18 and 24 degreesC within seven days. The most rapid germination occurred between 21 and 24 degreesC. At 32 degreesC, tot al germination was reduced to approximately 2%. At 35 degreesC, germination did not occur. Our data indicate that seeds of L. arboreus must be scarifi ed to obtain high germination percentages and the most rapids germination o ccurs between 24-29 degreesC.