Study on physiological and biochemical changes of Celtis sinensis seeds during stratification

This study aimed to explore the effects of stratification treatment on breaking the dormancy of Celtis sinensis seeds. The changes in nutrients, endogenous hormones and key enzyme activities during the stratification process were analyzed to clarify its hibernation release mechanism and find the best method for breaking seed dormancy.

Three treatment methods were adopted for Celtis sinensis seeds: variable temperature stratification, low-temperature stratification, and gibberellin combined with low temperature stratification. The physiological indicators such as soluble sugar, soluble protein, starch, crude fat, glucose-6-phosphate dehydrogenase (G-6-PDH), lipase, indole acetic acid (IAA), gibberellin (GA₃), zeatin riboside (ZR), and abscisic acid (ABA) of the seeds under different stratification stages were detected to analyze the changing trends of these physiological indicators during the stratification process.

Stratification treatments can significantly increase the germination rate of Celtis sinensis seeds. The effect of gibberellin combined with low temperature stratification treatment is the best, with a germination rate of 54.7% after 100 days of stratification. As the stratification process progresses, the trends of physiological indicators in each treatment are similar: soluble sugar increased first and then decreased, and soluble protein, starch and crude fat were decomposed continuously. The activity of lipase and G-6-PDH enzyme was enhanced continuously. IAA increased first and then decreased, ABA decreased continuously, and the contents of GA₃ and ZR increased continuously. The ratios of IAA/ABA, GA₃/ABA and ZR/ABA increased continuously. Gibberellin combined with low temperature stratification treatment showed significantly higher enzyme activity and GA₃ content in the middle and later stages of stratification compared to the other two treatments, while the ABA content was significantly lower than those of the other two treatments.

Stratification treatment effectively broke the dormancy of Celtis sinensis seeds, and the method of gibberellin combined with low temperature stratification is the best. During the stratification process, the nutrients, enzyme activities and endogenous hormone contents within the seeds are mutually transformed, jointly promoting the transition of Celtis sinensis seeds from dormancy to germination.