Comprehensive Transcriptomics, Hormone Metabolomics, and Physiological Analysis Reveal the Mechanism of Exogenous GA₄₊₇ Breaking the Seed Dormancy in <i>Polygonatum cyrtonema</i> Hua

<i>Polygonatum cyrtonema</i> Hua <i>(P. cyrtonema)</i> is a medicinal plant with high pharmaceutical value. Due to morphological and physiological dormancy mechanisms in <i>P. cyrtonema</i> seeds, natural germination rates remain exceptionally low. This biological constraint necessitates the development of protocols to shorten germination timelines and improve germination efficiency, which are critical requirements for advancing <i>P. cyrtonema</i> breeding programs. In this study, exogenous gibberellin A4 + A7 (GA₄₊₇) was applied to break dormancy in <i>P. cyrtonema</i> seeds. Transcriptomic, hormone metabolomic, and physiological analyses were then employed to investigate the underlying mechanisms. Germination tests revealed that 50 mg·L⁻¹ GA₄₊₇ was the optimal concentration to break dormancy in <i>P. cyrtonema</i> seeds. Transcriptome analysis indicated that exogenous GA₄₊₇ induced the expression of genes involved in GA and ABA biosynthesis and signaling. A total of 19 differential hormone metabolites were identified through hormone metabolomics, with significantly increased levels of active GA₁ and GA₄, but decreased levels of ABA content. These findings were consistent with the up-regulation of transcript levels of GA biosynthesis-related genes and the down-regulation of ABA biosynthesis-related genes, which resulted in an increase in active GA/ABA ratio. At the same time, it was found that exogenous GA₄₊₇ treatment induced sucrose and starch metabolism and pectin catabolic pathways. We measured the relevant physiological indicators and found that the content of soluble sugar and α-amylase activity increased, but the pectin content decreased. These findings establish a theoretical foundation for applying GA₄₊₇ in the standardized production of <i>P. cyrtonema</i>, particularly for accelerating breeding cycles in medicinal germplasm development.