An Overview of Environmental Cues That Affect Germination of Nondormant Seeds

For a successful germination and plant growth, seeds must germinate at the right time. Seeds must become nondormant and must fulfill the seed germination requirements. These requirements include light/dark, moisture, temperature, and other environmental cues (e.g., ethylene, exudate from host roots, or chemicals from fire) in the habitat. Seeds come out from dormancy in response to environmental cues, but depending on the species, they may need to be exposed to a second set of environmental cue to germinate. That is, nondormant seeds require specific temperature and water conditions to germination, and sometimes unfavorable temperature and water conditions will cause seeds to enter secondary dormancy. There are still mysteries about how/what environmental cues help seeds detect the right time/conditions for germination after dormancy is broken. Our knowledge of species-specific conditions is incomplete and further studies are needed.