Contrasting germination responses to vegetative canopies experienced in pre- vs. post-dispersal environments.

摘要: Background Seeds adjust their germination based on conditions experienced before and after dispersal. Post-dispersal cues are expected to be more accurate predictors of offspring environments, thus success, than pre-dispersal cues. Therefore, responses during seed maturation may superseded by imbibition. In taxa disturbed habitats, neighbours frequently reduce the performance germinants. This leads hypotheses that a vegetative canopy will in such taxa, imbibition over-ride maturation, since it is proximal cue immediate competition. These were tested here Arabidopsis thaliana METHODS: matured under simulated (green filter) or white light. Fresh (dormant) seeds imbibed dark, light at two temperatures (10 22 °C), proportions recorded. Germination was also recorded after-ripened (less dormant) induced into secondary dormancy dark each temperature, either with without brief exposure red far-red Key results Unexpectedly, expanded elicited germination, even as lost regained dormancy. contrast, an impeded had no effect germination. Maturation did not modify Seed masked genetic variation Conclusions The challenge hypothesis respond strongly own environment parents. observed relaxation requirements caused could maladaptive for disrupting Alternatively, reduced adaptive allowing germinate faster competition later stages though yet present seedling environment. masking canopy, moreover, impede evolutionary selection