Annual dormancy cycles in Lesquerella fendleri (Brassicaceae) seeds storedunder both field and laboratory conditions

Patterns of germination over time were investigated in a short-lived desert perennial species, Lesquerella fendleri (Gray) S. Wats. Field-collected se eds were either buried in the field in cloth bags or stored in a glass jar under laboratory conditions. Regular germination tests were conducted under a range of alternating temperatures (buried seeds) or under differing wate r regimes (laboratory-stored seeds). Testing revealed Lesquerella fendleri to have an annual dormancy-nondormancy cycle, which was manifest regardless of seed storage conditions, suggesting that cycles may be partially endoge nously regulated. Increasing seed germinability in field-stored seeds (maxi mum of 30% in year 1 and 95% in year 2) leads to the formation of a seed ba nk for at least 1 year and enhances the possibility of spreading germinatio n events through time. This allows parent plants to maximize fitness in ran domly fluctuating environments. The existence of two seedling flushes in th e field and single germinability peaks in growth chambers suggests that dor mancy cycling may support the formation of a metapopulation with subpopulat ions which are, although physically intermingled, genetically distinct.