Patterns of seed mass variation and their effects on seedling traits in Alliaria petiolata (Brassicaceae)

Seed mass is considered to be the least plastic component of reproductive y ield. Yet, in invasive populations of garlic mustard, Alliaria petiolata, s eed mass was highly variable (eightfold among populations. 2.5-7.5 fold wit hin populations, two-threefold within individuals, and 1.4-1.8 fold within fruits). Variation in seed mass among populations explained nearly half of the total variance. Variation among seeds within fruits accounted for a fur ther 25% of variance. individual seed mass within a plant decreased with in creased distance From the main stem, suggesting that access to parental res ources limits seed size in a predictable manner. MANOVAs and Roy-Bargmann s tepdown analyses revealed significant effects of seed mass, but not seed po sition (within a fruit or within an infructescence), on an array of subsequ ent seedling traits. Smaller seeds germinated significantly earlier, and se edlings from small seeds produced their first primary leaves significantly later and grew significantly taller After accounting for seed mass as a cov ariate, only one seedling trait, date of first leaf emergence, was affected by seed position in a fruit. Differences in seed mass may therefore affect seedling recruitment via effects on early seedling growth in this weedy sp ecies.