Secondary Seed Dormancy in Coreopsis lanceolata

We examined physical and physiological factors that control germination in the herbaceous perennial, Coreopsis lanceolata L. (Asteraceae). Seeds stored in paper envelopes for 6 to 18 months at room temperature were tested for germination on moistened filter paper in petri dishes. Germination percentages were greatest at 15 and 25 C and 12 h light/dark cycles. Germination percentages of imbibed seeds were not affected by previous storage at -10 C. Imbibed seeds subjected to 5 C entered a secondary dormancy that could not be broken by subsequent warmer temperatures, light/dark cycles or freezing temperatures. This study is the first of which we are aware documenting secondary dormancy in a perennial species. Secondary dormancy in C. lanceolata may be a mechanism for spreading the risk of recruitment.