目的 灰毡毛忍冬Lonicera macranthoides干燥的花蕾或带初开的花作为山银花入药，由其自然突变株培育的湘蕾品种具有花冠不展、花蕾期长的特殊表型，拟从细胞和分子水平探究湘蕾品种花冠不展开特殊表型的可能原因。方法 以常规和湘蕾型灰毡毛忍冬花为研究对象，采用光学显微镜观察花冠近轴面表皮细胞以及花冠纵切面组织形态；qRT-PCR检测木葡聚糖内转糖苷酶/水解酶LmXTH6、LmXTH7、LmXTH33，扩展蛋白LmEXP7以及果胶甲酯酶LmPME28、LmPME45的表达模式；STRING数据库预测蛋白互作网络；钌红染色结合Image J定量评估花冠纵切面细胞壁果胶去甲酯化程度。结果 常规型灰毡毛忍冬花冠近轴面表皮细胞呈现顺序扩张趋势，表现为基部优先扩张，随后中部扩张的趋势；且近轴面细胞的扩张速率大于远轴面；相比之下，湘蕾近轴面细胞扩张速率显著降低，细胞扩张程度不明显。分子层面，LmXTH6、LmXTH7、LmXTH33在常规品种开花前期及开花期高表达，在湘蕾品种中表达受到显著抑制；LmEXP7在常规花冠展开前表达量达到峰值，同一时期在湘蕾中表达较低。钌红染色结果表明湘蕾的整体去甲酯化程度高于常规，与LmPME28、LmPME45表达趋势一致。结论 灰毡毛忍冬湘蕾品种花冠不展开与花冠细胞扩张受到抑制密切相关，XTHs及EXP的低表达共同导致了湘蕾花冠细胞的扩张能力下降，PMEs的上调增加了细胞壁果胶去甲酯化，可能增强了细胞壁刚性。XTH/EXP-PME协同可能是导致湘蕾花冠不展开的重要原因，其为湘蕾灰毡毛忍冬优良表型调控机制研究提供了实验依据，也为理解植物花器官形态建成的细胞壁调控机制提供了新见解。

Objective Dried flower buds or newly opened flowers of Lonicera macranthoides are used as Shanyinhua (Lonicerae Flos) for medicinal purposes. The Xianglei cultivar, developed from a natural mutant, exhibits a distinctive phenotype characterized by non-opening corolla and prolonged bud stage. Aiming to elucidate the cellular and molecular mechanisms underlying this unique corolla phenotype. Methods The flower of conventional cultivar (WT) and the Xianglei cultivar (XL) of L. macranthoides were used as materials. Corolla adaxial epidermal cells and longitudinal sections were observed using light microscopy. The expression patterns of xyloglucan endotransglucosylase/hydrolase genes (LmXTH6, LmXTH7, LmXTH33), expansin gene (LmEXP7), and pectin methylesterase genes (LmPME28, LmPME45) were analyzed by qRT-PCR. Protein-protein interaction networks were predicted using the STRING database. Ruthenium red staining coupled with Image J quantitative analysis was performed to assess the degree of pectin de-methylesterification in corolla cell walls. Results In the WT, the adaxial cells of corolla displayed a spatially sequential expansion, with the basal cells expanding first, followed by the middle cells. Moreover, the expansion rate of the adaxial cells is higher than that of the abaxial cells. In contrast, the expansion rate of the adaxial cells is significantly decreased in Xianglei, and the extend of cell expansion is not evident. Molecular analyses revealed that LmXTH6, LmXTH7, and LmXTH33 were highly expressed during the pre-anthesis and anthesis stages in WT, but were significantly suppressed in Xianglei. Expression of LmEXP7 peaked just before corolla opening in WT but remained low in Xianglei at the same stage. Furthermore, ruthenium staining showed a higher overall degree of pectin de-methylesterification in Xianglei compared with WT, which is consistent with the expressin patterns of LmPME28 and LmPME45. Conclusion The non-opening of the corolla in the L. macranthoides cultivar Xianglei is closely associated with inhibited expansion of corolla cells. The low expression of XTHs and EXP collectively contributes to the reduced expansion capacity of corolla cells in Xianglei, while the up-regulation of PMEs increases pectin de-methylesterification in the cell wall, potentially enhancing cell wall stiffness. The synergistic effect of XTH/EXP and PME may be an important factor leading to corolla non-opening in Xianglei. These findings provide experimental evidence for understanding the regulatory mechanisms underlying the superior phenotype of the Xianglei cultivar and offer new insights into the cell wall regulatory mechanisms governing floral organ morphogenesis in plants.

R282.12

国家自然科学基金资助项目（82373992）；国家现代农业产业技术体系（CARS-21）；湖南省中药材产业技术体系专项（HARS-11）；2020年湖南省一流专业建设点：中药资源与开发；湖南中医药大学重点学科中药学科（校行发规字[2023]2号）；2025湖南中医药大学研究生科研创新项目（2025CX077）