Seed dormancy cycling in response to seasonal environmental signals

摘要

How seeds sense and respond to environmental signals under variable field conditions remains little understood. Research on the mechanisms that regulate dormancy and the completion of germination have largely been conducted in the laboratory and focused on a crop orientated view where dormancy is established at shedding (primary dormancy) and then declines at a rate determined by the ambient environment (Finch-Savage et al 2006). However, field observations in natural conditions show seeds respond toa range of environmental signals so that the depth of dormancy is continually changing in a cycle linked to the seasons. This process determines the time and climate space in which the seed will complete germination and establish a plant. It is therefore a critical component of the plant life cycle that is likely to be significantly affected by climate change. We have investigated whether the mechanisms identified in the laboratory can explain ecological observations of dormancy cycling in the field, and have begun to investigate the impact of global warming on this seed behavior.