Early Stress Resilience in Turfgrass: Comparative Germination and Seedling Responses of Lolium perenne L. and Poa pratensis L. Under Osmotic and Salt Stress

Seed germination and early seedling development represent critical stages for turfgrass establishment under increasingly frequent drought and salinity constraints. This study evaluated the germination performance of three cultivars of Lolium perenne L. and three cultivars of Poa pratensis L. exposed to iso-osmotic drought stress simulated with polyethylene glycol (PEG) and salt stress induced by NaCl. Germination percentage, mean germination time, germination index, seedling vigor index, and radicle and plumule elongation were quantified, and post-stress recovery tests assessed the reversibility of stress effects. Osmotic restriction imposed by PEG caused stronger inhibition of germination and seedling growth than NaCl at equivalent water potentials. L. perenne showed higher overall tolerance, maintaining faster emergence and greater seedling vigor across treatments, while P. pratensis was more sensitive but exhibited substantial germination recovery after stress removal. Cultivar-dependent variation was evident in both species, and multivariate analyses consistently differentiated tolerant and sensitive genotypes. The contrasting germination strategies, with rapid activation in L. perenne and delayed, recovery-oriented germination in P. pratensis, highlight species-specific adaptive responses to water and salt stress. These findings provide a physiological basis for selecting resilient turfgrass cultivars suited to drought- and salinity-prone environments, contributing to sustainable turfgrass establishment and management.