Germination of grass caryopses at increasing water deficit under simulated current and future temperature regimes

Our proposal was to study the impacts of increasing water stress and temperature on the survival and germination of caryopses of neotropical grass species occurring in dry- and wet grasslands of the Cerrado biome (Brazil). The Cerrado is the second largest biome of the South America, largely covered by savanna and other vegetation types subjected to periodic fires, as the grasslands. Considering that dry grasslands are subjected to higher soil temperatures and water deficit than wet grasslands, our expectation was that caryopses from dry grassland species would be more tolerant to both increasing water stress and higher temperatures (predicted for the future) than caryopses from wet grassland species. We found that more intense water stress reduced the survival of caryopses for both dry and wet grassland species. Temperature regime predicted for the future reduced the viability of wet grassland species and affected the germination strategy of dry grassland species. These results indicate that increasing water stress and temperature predicted for the future may compromise the recruitment potential of dry and wet grassland species, thus directly impacting the dynamics and resilience of these ecosystems in a future scenario.
This study was recently accepted for publication at the American Journal of Botany (2022). The table here provided brings data on the germinability (%), median germination time (T50, in hours) and viability (%) of neotropical grass caryopses from dry and wet grasslands subjected to increasing water stress treatments under simulated current and future temperature regimes. We have organized the data to facilitate its analysis in R. It is quite self-explanatory, but one can find a tab (metadata) which details each variable. The R script used in the present study is also provided.