Seed dormancy depends on seed size and seasonality

A case study in the legumes shows strong correlations between seed dormancy and environmental variables

Montigena novae-zelandiae
Montigena novae-zelandiae by josiedawber via NatureWatchNZ. Photo licensed under CC BY-NC 4.0.

In climates with unpredictable seasonal patterns, the ability of seeds to remain dormant provides ecological advantages by restricting germination to favorable growth periods. With aseasonal climates, however, this trait may be maladaptive.

In this study, researchers used a GBIF-mediated dataset of 216,600 legume (Fabaceae) family occurrences combined with data on climate, dormancy status and seed size to investigate the biogeography of seed dormancy and trait associations.

The distribution of plants exhibiting the trait is more prevalent in temperate zones, whereas seed size is inversely correlated with latitude. They propose a model in which the dormancy trait depends on seed size and seasonality, and this is supported the emperical results. Seed size alone, however, appears to be the better predictor of dormancy.

They suggest that the patterns uncovered will translate across ecological and phylogenetic scales- that aseasonal climates will be dominated by plants producing larger, nondormant seeds, while smaller, dormant seeds will predominate seasonal habitats.

Citations

Rubio de Casas R, Willis CG, Pearse WD, Baskin CC, Baskin JM and Cavender-Bares J (2017) Global biogeography of seed dormancy is determined by seasonality and seed size: a case study in the legumes. New Phytologist. Wiley-Blackwell 214(4): 1527–1536. Available at: https://doi.org/10.1111/nph.14498.

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