Breaking of seed dormancy by moist cold stratiп¬Ѓcation involves complex interactions in cells. To assess the effect of moist cold stratiп¬Ѓcation on dormancy break in seeds of Celtis koraiensis Nakai, we monitored percentages of germination and changes in endogenous plant growth regulators, sugars, protein, amino acids, and some enzymes after various periods of cold stratiп¬Ѓcation. Fresh seeds incubated at 4/15°C for 24 weeks germinated to 33.0%, while those cold stratiп¬Ѓed under constant temperature (4 or 15°C) has a lower germination percentage. Exogenous Gibberellic acid (GA₃) pretreatment resulted in a significant increase in the final germination. The highest percentage of germination was observed in seeds treated with 400 mg l^-1 GA₃ at alternating 4/15°C (from 13.5 to 45.2%).The total abscisic acid (ABA) content of seeds cold stratiп¬Ѓed for 5 months declined. Endogenous GA increased 2 fold during 5 months of cold stratiп¬Ѓcation. Trans-zeatin-riboside (ZR) and indole-3-acetic acid (IAA) also increased. In addition, the dynamic activity of endogenous plant growth regulators (PGRs) in the seeds treated with GA₃ differed significantly from the control. Concentrations of total soluble sugars and amino acids increased, while protein and lipid content decreased. The biological activity of glucose-6-phosphate dehydrogenase (G-6PDH) and α-amylase increased in the seeds with diverse stratiп¬Ѓcation times. The catabolism of storage products was almost consistent with the changes of their enzymes. Hence, the requirement of temperature fluctuation acts as an environmental cue for the successful germination of these Korean Hackberry seeds. GA₃ increased the germination percentage. A dormancy break occurs during cold stratiп¬Ѓcation, seeds of Korean Hackberry undergo changes in PGRs, storage product, and enzyme content.