Establishing an efficient in vitro regeneration of Toona sinensis (A.Juss.) Roem. (T.sinensis) is critical for advancing industrial applications. However, current regeneration efforts are constrained by low efficiency and challenges in redifferentiation. In this study, hypocotyls and leaves of T.sinensis were utilized as explants for the establishment of a regeneration system and optimization of age, distribution site of explants, and orientation. Hypocotyls of 21-day-old seedlings were placed horizontally on a medium containing plant growth regulators (PGRs): 0.75 mg/L Zeatin (ZT), 0.15 mg/L Indole acetic acid (IAA), and 0.05 mg/L 2,4-Dichlorophenoxyacetic acid (2,4-D). The callus induction rate of hypocotyls was 73.03%, with an average of 14.80 adventitious buds per callus. The proximal ends of leaves in the second developmental stage were placed upright on a medium with 1.0 mg/L ZT, 0.05 mg/L IAA, and 0.20 mg/L 2,4-D. The callus induction rate of leaves was 77.77%, with an average of 15.78 adventitious buds per callus. Additionally, the proliferation and rooting of regenerating buds were investigated. When regenerated shoots were transferred to a proliferation medium containing 1.5 mg/L 6-Benzylaminopurine (6-BA) and 0.1 mg/L Indole-3-butyric Acid (IBA), shoot proliferation coefficients peaked at 4.18 for leaves and 3.17 for hypocotyls. Transferred these proliferating buds to the rooting medium, reached a 100 % rooting rate with PGRs at 1.0 mg/L, and the survival rate of regenerated plants after transplanting reached 98 %. This study establishes a more efficient in vitro regeneration system for T.sinensis, offering a robust foundation for molecular breeding efforts. The results have the potential to support molecular improvement breeding and the innovation of germplasm resources of T.sinensis.

中文翻译：

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多功能木本植物香椿叶和下胚轴体外高效再生系统的建立


建立香椿 （A.Juss.） 的有效体外再生罗姆。（T.sinensis） 对于推进工业应用至关重要。然而，目前的再生工作受到效率低和再分化挑战的限制。在本研究中，以 T.sinensis 的下胚轴和叶子为外植体，用于建立再生系统并优化年龄、外植体分布位点和定向。将 21 日龄幼苗的下胚轴水平放置在含有植物生长调节剂 （PGR） 的培养基上：0.75 mg/L 玉米素 （ZT）、0.15 mg/L 吲哚乙酸 （IAA） 和 0.05 mg/L 2,4-二氯苯氧乙酸 （2,4-D）。下胚轴愈伤组织诱导率为 73.03%，平均每间愈伤组织不定芽 14.80 个。将第二发育阶段叶片的近端直立放置在含有 1.0 mg/L ZT、0.05 mg/L IAA 和 0.20 mg/L 2,4-D 的培养基上。叶片愈伤组织诱导率为 77.77%，平均每根愈伤组织不定芽 15.78 个。此外，还研究了再生芽的增殖和生根。当将再生芽转移到含有 1.5 mg/L 6-苄氨基嘌呤 （6-BA） 和 0.1 mg/L 吲哚-3-丁酸 （IBA） 的增殖培养基中时，叶子的芽增殖系数峰值为 4.18 和 下胚轴的 3.17。将这些增殖芽转移到生根培养基中，以 1.0 mg/L 的 PGR 达到 100 % 的生根率，移栽后再生植株的成活率达到 98 %。本研究建立了一种更有效的 T.sinensis 体外再生系统，为分子育种工作提供了坚实的基础。 研究结果具有支持中华木竹分子良种育种和种质资源创新的可能。