Divergent regulation of seed mass on roots and leaves in legume plants

Abstract Seed mass is a key trait influencing plant form and function. It reflects parental resource investment and influences seedling growth as well as the construction of root and leaf organs. However, how seed mass regulates root and leaf functional traits in legume species remains unclear. In this study, we selected 16 common herbaceous legume species growing in pots. The results showed that seed mass exhibited a U-shaped quadratic relationship with both fine root diameter and fine root biomass. Seed mass was significantly positively correlated with single leaf area, specific leaf area, and stomatal length. However, it showed no significant correlation with leaf nitrogen concentration, leaf vein traits, or stomatal density. Meanwhile, the relationships between seed and root traits and between seed and leaf traits in these legume species were markedly different from those reported for global non-nitrogen-fixing plants. In summary, seed mass may selectively regulate certain root and leaf traits. These findings provide a new perspective for understanding the formation of life history strategies in legumes and their responses and adaptations to environmental change.