
· Seed water uptake is the first physiological process initiating germination, yet broad-scale variation in seed imbibition dynamics across plant species remains poorly explored. · Here, we compiled a global dataset of 203 species representing 64 families and quantified maximum water absorption capacity, water uptake rate, lag phase, seed mass, seed coat thickness, embryo-to-seed length ratio (EL/SL), and embryo-to-seed surface ratio (ES/SS). Phylogenetic comparative analyses were used to evaluate trait variation, phylogenetic signal, and evolutionary optima. · Cultivated species differed most consistently from wild species in seed morphology, showing larger seed mass, thinner seed coats, and lower embryo-to-seed ratios. In contrast, water absorption traits showed limited evidence of consistent differentiation between cultivated and wild species. Phylogenetic signal was generally strong for seed morphological traits, whereas hydration dynamics, particularly lag phase, exhibited weaker and more variable phylogenetic structure. Models suggested distinct evolutionary optima in cultivated versus wild species for several seed morphological traits, particularly seed mass, seed coat thickness, and embryo ratios whereas support for divergence in evolutionary optima of water absorption traits was comparatively weaker. · This study provides an evolutionary framework for understanding variation in seed functional traits and highlights seed water relations as an important but underexplored axis of plant functional biology.
