5-AzaCytidine Promotes Somatic Embryogenesis of Taxodium Hybrid ‘Zhongshanshan’ by Regulating Redox Homeostasis

DNA methylation plays a crucial role in regulating the developmental processes of plants. Particularly, it is closely associated with the development of embryogenic cells (EC) and somatic embryos (SE). In this study, we investigated the effects of 5-azaCytidine (5-azaC) treatment on somatic embryogenesis proliferation and maturation of <i>Taxodium</i> hybrid 'zhongshanshan'. The results showed that the callus proliferation was inhibited when the concentration of 5-azaC exceeded 30 μM, while treatment with 5 μM 5-azaC improved the maturation rate and expedited the process of SE formation. It was also noted that 5-azaC influenced somatic embryogenesis during the second week of embryo induction, substantially enhancing the maturation rate of somatic embryos and the germination rate of <i>Taxodium</i> hybrid 'zhongshanshan'. Furthermore, the analysis revealed that treatment with 5-azaC resulted in elevated levels of H₂O₂, SOD, POD, and AsA during the cotyledonary embryo period in <i>Taxodium</i> hybrid 'zhongshanshan', indicating its potential to promote somatic embryogenesis by regulating redox homeostasis. This study concluded that 5-azaC could improve the efficiency of somatic embryogenesis in <i>Taxodium</i> hybrid 'zhongshanshan', as well as provide a solid foundation for investigating the effects of 5-azaC on somatic embryogenesis in other conifer species.