Effects of H 2 SO 4 and Gibberellin A 3 on Dormancy Release of Tilia miqueliana Seeds

Seed dormancy and germination are distinct physiological processes. The transition from dormancy to germination is a critical developmental step in the lifecycles of plants and is important for forestry production, particularly in deeply dormant woody seeds. The induction and release of dormancy are controlled by various regulators, some of which are plant hormones. Tilia seeds are deeply dormant for 2–3 years under natural conditions, although treatment with H 2 SO 4 -GA 3 can rapidly break dormancy. In this study, changes in physiological (endosperm cell structure and morphology), biochemical (sugars, starch, protein, and fat), and endogenous hormones [gibberellin (GA), abscisic acid, trans-zeatin-riboside, and indole-3-acetic acid] during dormancy release were measured. The results showed that treatment with H 2 SO 4 -GA 3 significantly improved the respiratory intensity. A considerable number of holes and cracks appeared in the outer and inner endosperm cells. Additionally, the metabolism of sugars, starch, protein, and fat was facilitated, and their content decreased significantly. The release from dormancy was also associated with increases in GA, ZR, and IAA, decreases in ABA, and higher ratios of GA/ABA, ZR/ABA, and IAA/ABA. The results of this study improve our understanding of the changes in endosperm metabolism and the roles of hormones during dormancy release in Tilia miqueliana seeds. They will enable the dormancy regulatory mechanism in Tilia to be determined and lead to practical applications in breeding.