Gibberellin-induced germination enhancement in Chinese sour jujube seeds under cold stress

• Exogenous GA₃ enhances Chinese sour jujube seeds germination performance. • Prolonged low-temp exposure lowers soluble sugars, raises stress markers and antioxidant enzymes, indicating GA₃ enhances stress tolerance via priming. • GA₃ modulates phenylpropanoid/zeatin pathways via up-regulating 4CL/CCR and down-regulating CKX. Low temperature stress severely hinders Chinese sour jujube ( Ziziphus jujuba var. spinosa (Bunge) Hu ex H. F. Chow) seed germination, threatening agricultural yields. Although Gibberellin A3 (GA 3 ) regulates seed germination, its role in alleviating low temperature stress and its potential mechanisms in Chinese sour jujube are still unclear. This study determined the optimal GA 3 concentration (150 mg/L via concentration gradient experiments under 15°C) to improve germination under cold stress, analyzing phenotypes physiological indices, and integrating metabolomics and transcriptomics analysis. Results showed 150 mg/L GA 3 increased germination rate (23%) and vigor (18%), enhancing antioxidant enzyme activities and proline levels to reduce oxidative damage during prolonged cold exposure. Comprehensive metabolomics and transcriptomics analysis showed that phenylpropionic acid/zeatin biosynthesis gene ( 4 CL, CCR ) was up-regulated, while cytokinin dehydrogenase ( CKX ) and PAL were down-regulated, which were related to the increase of zeatin and the decrease of abscisic acid metabolites. This study clarified the GA3-mediated cold-resistant mechanisms of Chinese sour jujube, which provided a basis for breeding cold-resistant varieties and optimizing germination scheme under low temperature stress.