Habitat and species effects on seed formation and emergence performance in Cerrado graminoids

Environmental conditions where plants occur can influence seed formation and physiological attributes, such as dormancy and longevity, with implications for management, conservation, and restoration of natural ecosystems. In the Cerrado, tropical grasslands occur in a wide range of hydrological regimes, from prolonged dry to permanently waterlogged soils, which may influence the establishment strategies of herbaceous species. In this study, we evaluated seed mass, formation, and emergence performance in six graminoid species across dry and wet Cerrado grasslands, examining how grassland type, species, and storage time affect seed attributes.

We collected seeds from five Poaceae and one Cyperaceae species in four dry and three wet grasslands within Chapada dos Veadeiros National Park, in Central Brazil. From each grassland, we selected and weighed a sample of 100 full seeds per species. To evaluate seed formation, we used X-ray imaging. Then we assessed and analyzed seed emergence in a randomized, fully factorial design, considering the two grassland types (dry and wet) and three storage times (freshly harvested - no storage, 6, and 12 months).

Seed mass, formation, and emergence were influenced by both habitat type and storage time, but species were the main source of variation. Echinolaena inflexa, Aristida setifolia, Trachypogon macroglossus, and Loudetiopsis chrysothrix produced heavier seeds and had a higher percentage of full seeds in wet grasslands. Storage improved seed emergence for these species when collected from dry grasslands but generally had no effect or an opposite trend in seeds from wet grasslands. Schizachyrium tenerum and Rhynchospora speciosa showed no habitat-related differences.

Differences between dry and wet grasslands influence seed attributes in populations of most, but not all, graminoid species, revealing inter- and intraspecific variation. Accordingly, management and restoration strategies should consider species-specific responses to habitat and storage conditions rather than rely on generalizations.