Germination and seed bank dynamics of dimorphic seeds

Heteromorphic seeds can show differences in dormancy and germination, but it is not known how this affects maintenance and regeneration of populations. Cao et al. bury different seed morphs of an annual halophyte, Suaeda corniculata, and examine germination dynamics at monthly intervals over 2 years. They find that black seeds have an annual dormancy/non-dormancy cycle that is absent in brown seeds, and they also exhibit an annual cycle in sensitivity of germination to salinity. Brown seeds form only a transient soil seed bank whilst black seeds form a persistent one. They conclude that differences in performance of the two seed morphs in the soil seed bank increase fitness of the species in unpredictable saline environments.