Osmotic stress promotes somatic embryogenesis of Fraxinus mandshurica, which leads to accumulation of reactive oxygen species (ROS). The single pieces of cotyledons of F. mandshurica were used as explants to induce somatic embryogenesis in osmotic-stress medium. Furthermore, the hydrogen peroxide (H₂O₂) content of explanted cells was varied by adding exogenous H₂O₂ or catalase solution to assess the effects of the exogenous H₂O₂ on somatic embryogenesis, intracellular H₂O₂ accumulation, and the relationship between signaling mediated by ROS or reactive nitrogen species. The results revealed that exogenous H₂O₂ (100‒300 μmol L^–1) increased the number of somatic embryos. On 60th day of exogenous H₂O₂ (200 μmol L^–1) treatment, the number of somatic embryos of explants treated, which was 136.54%, was higher than the control. Moreover, exogenous H₂O₂ (100 μmol L^–1) significantly increased the intracellular H₂O₂ content and enhanced the activities of superoxidase dismutase and peroxidase. Finally, exogenous H₂O₂ (100 μmol L^–1) activated the intracellular non-enzymatic pathway for nitric oxide (NO) synthesis. The somatic embryogenesis in broadleaf trees increases with the change of endogenic ROS content, and depends on the upregulation of antioxidant enzymes. Both H₂O₂ and NO, as signaling molecules, were found to be involved in the process of somatic embryogenesis in broadleaf trees. In the process of exogenous H₂O₂ promoting somatic embryogenesis, NO synthesis depended on non-enzymatic reactions. These results provide a scientific basis for resolving the mechanism by which ROS levels are regulated during somatic embryogenesis of broadleaf trees and establish a reasonable and efficient technology system for regulating somatic embryogenesis of trees.

渗透胁迫促进水曲柳的体细胞胚发生，从而导致活性氧（ROS）的积累。曼氏镰刀菌的子叶单片用作外植体，以在渗透压培养基中诱导体细胞胚发生。此外，通过添加外源H ₂ O ₂或过氧化氢酶溶液来改变外植细胞的过氧化氢（H ₂ O ₂）含量，以评估外源H ₂ O ₂对体细胞胚发生，细胞内H ₂ O _{2的影响。}积累，以及由ROS或活性氮物种介导的信号传导之间的关系。结果表明，外源H ₂ O ₂（100‒300μmolL ^–1）增加了体细胞胚的数量。在外源H ₂ O ₂（200μmolL ^–1）处理的第60天，处理的外植体的体细胞胚数为136.54％，高于对照组。此外，外源H ₂ O ₂（100μmolL ^–1）显着增加了细胞内H ₂ O _2的含量，并增强了过氧化物酶歧化酶和过氧化物酶的活性。最后，外源H ₂O ₂（100μmolL ^–1）激活了细胞内非酶促一氧化氮（NO）合成的途径。阔叶树的体细胞胚发生随着内源性ROS含量的变化而增加，并取决于抗氧化酶的上调。发现H ₂ O ₂和NO作为信号分子都参与了阔叶树的体细胞胚发生过程。在外源H ₂ O ₂的过程中促进体细胞胚发生，NO合成取决于非酶反应。这些结果为解决阔叶树体细胞胚发生过程中ROS水平的调控机制提供了科学依据，为树体体细胞胚发生的调控建立了合理有效的技术体系。