Germination Strategies of Heteromorphic Seeds and Their Implications for Coastal Wetland Restoration in Suaeda heteroptera

Coastal wetlands are increasingly threatened by salinization and habitat degradation, which limit the natural regeneration of native halophytes. Suaeda heteroptera, an important halophytic species in temperate coastal wetlands, plays a critical role in vegetation restoration; however, its population recovery is constrained by limited seedling establishment. This study investigated the effects of seed heteromorphism, chemical priming, and environmental factors on the germination performance of S. heteroptera to provide insights for sustainable coastal wetland restoration. Two heteromorphic seed types of S. heteroptera were evaluated under potassium permanganate (KMnO4), gibberellin (GA), and different salinity, temperature, and photoperiod conditions. The results revealed distinct germination strategies between seed types: Type B seeds showed faster germination initiation and higher early germination performance, whereas Type A seeds exhibited delayed germination characteristics, indicating differences in regeneration strategies between the two seed morphotypes. Both KMnO4 and GA showed concentration-dependent effects, with low concentrations promoting germination and excessive concentrations inhibiting germination. Orthogonal analysis indicated that temperature had the greatest relative influence on germination, followed by salinity and photoperiod conditions. Within the tested experimental range, the optimal germination performance was observed under 10‰ salinity, 10 °C, and 24 h light exposure. These findings demonstrate that seed heteromorphism provides complementary regeneration strategies for S. heteroptera and that integrating chemical priming with environmental regulation may provide useful insights for coastal wetland restoration.