Germination and dormancy of seeds in Echinacea purpurea (L.) Moench (Asteraceae)

Seeds of Echinacea purpurea (L.) Moench display low germination rates and a wide variation in rates of emergence, hindering production considerably. A few factors, all known to affect germination of Echinacea purpurea seeds were investigated. It was found that treatments of gibberellic acid (GA(3)) and ethephon significantly increased germination percentage and shortened mean germination time (MGT) and prechilling treatment resulted in a large increase in percentage and rate of germination, both in darkness and in light. A prechilling treatment for 14 days at 4 degrees C in a 200 mg/L GA(3) or 1 mM ethepon solution in continuous fight, followed by a germination period in light at 20/30 degrees C (16/8h), induced over 90% seed germination. In addition, removing the seed coats or damaging the seeds, also proved to be conductive to improving seed germination. The experimental results showed that dormancy of E. purpurea seeds is partly due to seed coat restriction. The dormancy mechanisms are discussed.