Physiological responses of seed dormancy and germination to cold stratification in Phoebe hui Cheng ex Yang

Phoebe hui Cheng ex Yang is a rare and unique tree species in China, and its seeds exhibit physiological dormancy. In this study, we explored the physiological characteristics of P. hui seeds under cold stratification to reveal the response mechanism related to dormancy and germination. Specifically, we used P. hui seeds under different cold stratification time (0, 20, 40, and 60 d) to study the effects on germination percentage, nutrient levels (starch, soluble sugar, and soluble protein), peroxidase (POD) activity, and endogenous hormone levels (abscisic acid (ABA), gibberellin (GA₃), auxin (IAA), and zeatin nucleoside (ZR)), and further analyzed the correlation between seed germination and physiological indicators. Results showed that: (1) Cold stratification effectively broke P. hui seed dormancy, with stratification for 60 d showing the best effect. (2) With cold stratification, seed germination time shortened and germination percentage increased; starch content declined and soluble sugar and protein content increased; POD activity increased; ABA content decreased,GA₃ and IAA content increased, and ZR content first increased and then decreased. (3) Seed dormancy and germination of P. hui were closely related to changes in nutrient content, POD activity, and endogenous hormone content.