Predicting the influence of maternal effects on plant life cycles across landscapes

Background/Question/Methods

Through their life, organisms’ transition thorough multiple life stages that differ in environmental tolerances and responses. Therefore, predicting the seasonal timing of life cycles is critical for understanding how organisms will respond to environmental change. In particular, the environment experienced during reproduction often has trans-generational effects on seed dormancy that potentially limit reproductive output. Previously, we took a step towards this goal by creating a phenology model—parameterized for A. thaliana—that predicts whole life-cycle phenology of different genotypes in complex environments. We did this by linking together phenology (developmental threshold) sub-models describing each life-stage transition. Here we present new empirical data demonstrating how the environment during reproduction influences germination behavior in this species. Next, we incorporate these findings into the previously built life-cycle model to explore across the European range how maternal effects influence life-cycle phenology. Further we ask if these trans-generational effects alter the time favorable for reproduction or the environment experienced by developing seeds. 

Results/Conclusions

Laboratory experiments demonstrated that germination behavior of A. thaliana is strongly influenced by maternal environment with colder maternal temperatures reducing germination specifically in warm germination conditions. Further, genotypes differed in the plasticity of germination behavior to maternal environment and germination behavior changed as seeds age. We incorporated these results into our life-cycle model and projected life cycles for genotypes that varied in the expression of maternal effects at four sites. We found that both location and plasticity to maternal environment altered life-cycle phenology across the range. In some cases maternal effects reduced life-cycle variation within a location. Both factors influenced the environment during seed maturation and lead to variable windows for reproduction. Our results suggest that selection on trans-generational effects may vary across the range and can shape life-cycle expression of a species.