Effects of prolonged seed submersion on seedling establishment and early growth in wheat

Wheat seedlings are widely used as a fresh food source for herbivorous insects and as a model for studies of early plant development. Although the effects of seed soaking on wheat germination have been extensively investigated, much less is known about how prolonged pre-germination submersion influences subsequent seedling establishment and early growth. In this study, we examined the effects of seed submersion duration on germination, seedling growth, and biomass accumulation in two wheat cultivars under controlled laboratory conditions. Seeds were submerged in water for 0 to 336 h at 25°C before germination. Germination remained high after submersion for up to 48 h but declined markedly after 168 h or longer. More importantly, prolonged submersion delayed subsequent seedling development, increasing the time required for seedlings to reach leaf lengths of 5, 10, and 15 cm. Following a 24 h submersion treatment, leaf length increased rapidly until days 11–12 before reaching a plateau, whereas seedling dry weight continued to increase until approximately day 16. These results demonstrate that the effects of pre-germination water exposure extend beyond germination success and influence subsequent seedling establishment and early growth. Our findings provide practical guidance for optimizing wheat seedling production and emphasize the importance of evaluating post-germination performance when assessing the effects of prolonged seed submersion.