Abstract: This study aimed to elucidate the regulatory mechanisms underlying seed dormancy release in Aconitum kusnezoffii Reichb. by monitoring embryo-to-endosperm length ratio （embryo rate） and quantifying endogenous hormone levels and expression of related genes at key stratification stages. The embryo rate exhibited a “slow-rapid-slow” pattern： remaining stable at 23.31% from day 0 to 14， sharply increasing to 90.91% by day 42， followed by radicle elongation （0.75 cm at day 49） and cotyledon emergence at day 54. Hormone analysis showed a significant decline in abscisic acid （ABA） content （46.48% reduction compared to day 0）， while gibberellin A₃（GA₃）， indole-3-acetic acid （IAA）， methyl jasmonate （MeJA）， and brassinosteroid （BR） increased by 34.77%， 60.71%， 97.53%， and 17.95%， respectively. Zeatin riboside （ZR） content rose initially， and then declined. Ratios such as GA₃/ABA and IAA/ABA significantly increased， indicating enhanced antagonism from growth-promoting hormones against ABA during dormancy release. Expression analysis showed that key genes involved in hormone metabolism CYP707A2 （ABA degradation）， KAO （GA biosynthesis）， and YUCCA （IAA biosynthesis） were significantly upregulated， consistent with hormonal changes. Collectively， the continuous decline in ABA content may serve as a key driver of dormancy release， while increased GA₃， IAA， MeJA， and BR levels may synergistically and antagonistically interact with ABA signaling to promote embryo development and seed germination.

Key words: Aconitum kusenezoffii Reichb., Seed dormancy, Embryo-to-endosperm ratio, Hormone

摘要： 本研究以草乌头（Aconitum kusnezoffii Reichb.）种子为材料，通过监测胚率（胚长/胚乳长）动态变化，确定休眠解除的关键时期，并测定不同阶段内源激素含量及相关基因表达水平，以解析其休眠解除机制。结果显示，种子胚率在休眠解除过程中呈“慢–快–慢”变化趋势：0—14 d基本不变（23.31%），14—42 d迅速升高至90.91%，49 d起胚根伸长，54 d子叶出土。激素分析表明，在层积过程中，脱落酸（Abscisic acid，ABA）含量显著下降（较0 d降低46.48%），而赤霉素A₃（Gibberellin A₃，GA₃）、吲哚乙酸（Indole-3-acetic acid，IAA）、茉莉酸甲酯（Methyl jasmonate，MeJA）和油菜素内酯（Brassinosteroid，BR）含量分别升高34.77%，60.71%，97.53%和17.95%，玉米素核苷（Zeatin riboside，ZR）含量则呈先升后降趋势；GA₃/ABA，IAA/ABA等比值显著上升，表明生长促进类激素对ABA的拮抗作用增强。相关基因表达分析显示，层积过程中ABA降解基因CYP707A2，GA合成基因KAO和IAA合成基因YUCCA等表达量均上调，与激素变化趋势一致。研究表明，ABA的降低可能是休眠解除的关键驱动因素，GA₃，IAA，MeJA和BR等激素通过拮抗或协同ABA信号通路，共同调控种子由休眠向萌发的转变过程。

关键词: 草乌头, 种子休眠, 胚率变化, 激素