Comparison of seed desiccation sensitivity between Quercus chenii and Q.acutissima

Seed morphological traits and antioxidant defense mechanisms determine desiccation sensitivity differences between Quercus species, enabling development of species-specific seed storage protocols. Despite extensive research on the desiccation sensitivity of Quercus seeds, the factors and physiological mechanisms driving interspecific variations remain poorly understood. This study investigated the differences in desiccation sensitivity between Q. chenii and Q. acutissima seeds by examining the effects of desiccation on seed moisture content, detecting reactive oxygen species production, antioxidant enzyme activities, soluble sugars and proteins, and exploring the relationships among initial seed traits, water loss rates, and seed viability. Results showed that despite similar initial moisture content (41.9% for Q. chenii and 42.9% for Q. acutissima), Q. acutissima seeds exhibited more rapid water loss under identical desiccation conditions (same seed: silica gel ratio and temperature), primarily due to their larger scar area and seed mass, leading to a decline in germination percentage below 80% within just 7 days, while Q. chenii seeds maintained high germination percentage for up to 27 days. Regarding physiological mechanisms, Q. chenii seeds demonstrated a more efficient antioxidant defense system, characterized by higher superoxide dismutase activity and early increased catalase activity, which effectively reduced hydrogen peroxide accumulation and membrane lipid peroxidation. Additionally, Q. chenii showed significantly increased soluble protein content during early desiccation stages. These findings contribute to a deeper understanding of desiccation sensitivity mechanisms and their interspecific variations in recalcitrant seeds, providing physiological bases for optimizing recalcitrant seed conservation strategies.