【目的】通过优化欧洲小叶椴(Tilia cordata)体细胞胚胎诱导的培养基配比,筛选诱导其体胚发生及再生植株成苗的最适培养条件,从而建立完整的体胚发生体系。【方法】以欧洲小叶椴未成熟合子胚作为外植体,通过在培养基中添加不同浓度及配比的植物生长调节剂2,4-二氯苯氧乙酸[(2,4-D)和6-苄氨基嘌呤(6-BA)],探究其对体胚发生过程中愈伤组织的诱导、增殖及体胚诱导效率的影响;采用不同基础培养基、吲哚-3-丁酸(IBA)浓度及活性炭添加量的组合处理,探讨其对体胚萌发及再生植株成苗的影响。【结果】外植体诱导产生愈伤组织的最适2,4-D质量浓度为3.0 mg/L、6-BA为0.2 mg/L,诱导率达64.25%;胚性愈伤组织在2,4-D质量浓度为3.0 mg/L,6-BA为0.2 mg/L的培养基中增殖效果最佳,增殖系数高达1 063.72%;体胚诱导阶段的最适2,4-D质量浓度为3.0 mg/L,6-BA为0.2 mg/L,体胚诱导率达46.41%;当体胚转入添加0.5 mg/L IBA的无活性炭MS培养基上时,可成功诱导植株再生。【结论】初步建立了完整的欧洲小叶椴体胚发生体系,为后续椴树属植物的高效繁殖及遗传转化体系构建奠定了基础。

【Objective】This study aims to develop a complete somatic embryogenesis system for Tilia cordata by systematically optimizing the culture medium composition to identify optimal conditions for somatic embryo induction and subsequent plant regeneration.【Method】Immature zygotic embryos of T. cordata were used as explants. The effects of different concentrations and combinations of plant growth regulators 2,4-dichlorophenoxyacetic acid(2,4-D and 6-benzylaminopurine(6-BA) on callus induction, proliferation, and somatic embryo induction efficiency were systematically investigated. Additionally, the impacts of different basal media, indole-3-butyric acid(IBA) concentrations, and activated charcoal supplementation on somatic embryo germination and plant regeneration were evaluated.【Result】Optimal callus induction was achieved at a concentration of 3.0 mg/L 2,4-D combined with 0.2 mg/L 6-BA, yielding an induction efficiency of 64.25%. Subsequent proliferation of embryogenic callus demonstrated maximal growth potential under identical hormonal conditions (3.0 mg/L 2,4-D+0.2 mg/L 6-BA), as evidenced by an exceptional proliferation coefficient of 1 063.72%. For somatic embryo induction, the same hormonal formulation (3.0 mg/L 2,4-D+0.2 mg/L 6-BA) proved most effective, generating somatic embryos at a frequency of 46.41%. Complete plant regeneration was successfully accomplished through transfering of developed somatic embryos to MS basal medium supplemented with 0.5 mg/L IBA in the absence of activated charcoal, with all regenerated plants exhibiting normal morphological characteristics.【Conclusion】In this study, a complete somatic embryogenesis system of T. cordata was initially established, providing a basis for subsequent establishment of an efficient propagation and genetic transformation system for Tilia.