Gibberellin-induced germination enhancement in Chinese sour jujube seeds under cold stress
Qiang Chen, Guolong Li, Jin‐Ao Duan, Zhishu Tang, Zhongxing Song, Hongbo Liu, Xinbo Shi
Abstract
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.