Seed mass has been explored as an important functional trait of plants that impacts many aspects of plant performance, including dispersal distance, the timing of germination, post-emergent survival, and vegetative and reproductive productivity. To date, however, generalizations regarding the role of seed mass on these performance indices have been hampered by conflicting results among published experiments. Here, we report preliminary results from a meta-analysis focused on the influence of seed mass on the timing of germination. The length of time it takes for a seed to germinate is an important life history trait that is presumably under high selective pressure. For instance, the risk of germinating early and under potentially unfavorable conditions is theoretically balanced by the benefit of minimizing longer term risk of predation. We used Web of Science to search for published experiments that report results of the relationship between seed mass and several measures of plant performance: germination rate, survival, biomass production, and fecundity.
Results/Conclusions
Using the metafor package in the program R, we calculated 38 raw mean effect sizes and sample variances from seven peer-reviewed sources that report seed mass (0.07 – 27.2 mg), germinability (7 - 99%), and time since sowing (7 - 108 days) for 36 species of plants. After controlling for publication source and time since sowing, our multi-level meta-regression model suggests that germinability is positively influenced by seed mass. Germinability increased 0.72% (95% CI = 0.64 – 0.81%) with each unit (mg) increase of seed mass. Our preliminary conclusion is that seed mass is an important functional trait that has a generally positive influence on germinability of a wide variety of plant species. We aim to continue this work and include other moderators in future analysis, such as phylogeny, latitude, biome, dispersal strategy, and life cycle strategy.