Seed mass and germination in an alpine meadow on the eastern Tsinghai-Tibet plateau

In this study, we built up a database of 570 species from an alpine meadow on the eastern Tsinghai-Tibet plateau. We examined the correlation of seed mass and germination with phylogeny, habitat and altitude, and the relationship between seed mass and germination. We found that: habitats had no significant effects on seed mass and germinability, which was in accord with the former studies; there was a significant negative correlation between seed mass and altitude, as well as between germinability and altitude, which was opposite to most of the former studies; there was a significant negative correlation between seed mass and germinability, which was in contrast with other studies that have found a positive relationship, and seed mass could explain 24.1% of total variation in germinability; in GLM, family and genus accounted for 43.9% and 83.9% of total variation in seed mass, and 34.1% and 65.4% in germinability, respectively, thus, it was evident that seed mass and germinability were strongly related to phylogeny. We considered that seed mass and germination might be the result of both selective pressures over long-term ecological time and the constraints over long-standing evolutionary history of the taxonomic membership. We suggest that correlates of ecology and phylogeny should be taken into account in comparative studies on seed mass and germination among species.