The architecture of submergence escape in two contrasting accessions of the stoloniferous grass Paspalum denticulatum

Floodplains worldwide face an increasing risk of inundation due to climate change, underscoring the need to identify plant species capable of withstanding flooding. Paspalum denticulatum Trin. is a wetland stoloniferous grass emerging as suitable for cultivation in humid recreational areas or for water erosion control. This study evaluated the morphological responses to varying flooding intensities (waterlogging, partial submergence, and complete submergence) in two P. denticulatum accessions with contrasting growth habits, focusing on plant architecture. The upright accession from Paraguay, with a tall growth habit, showed greater internode length, longer second-order stolons, longer leaf sheath length, and prolonged stolon growth under flooding than at field capacity. Remarkably, the creeping accession from Argentina with a dwarf, prostrate habit, instead of deploying a quiescent state under partial or complete submergence, exhibited escape responses that mainly consisted of steeper stolon growth angles than in drained plants. Unexpectedly, creeping aerial relative growth rate (RGR) declined sharply during water drawdown, indicating an impaired recovery capacity. In conclusion, the upright accession demonstrated a superior capacity to adjust to fluctuating water levels and recover post-flooding, traits that are particularly advantageous for use in flood-prone recreational environments.