Establishment of Efficient Somatic Embryo Maturation System of Pinus elliottii.

Pinus elliottii, a key economic conifer in southern China, requires efficient propagation methods to meet demand for elite germplasm in resin and timber production. While somatic embryogenesis-based plant regeneration has been successfully achieved in Pinus elliottii, large-scale production remains challenging. Our results demonstrate that the genotype of Pinus elliottii significantly influences the induction rate of embryogenic callus. During somatic embryo maturation, the liquid-solid induction method increased the number of mature embryos by 25.85 times. Maturation efficiency was further enhanced by a 3-week pretreatment followed by the application of 9 mg/L ABA, 0.5 mg/L PSK, and 6 mg/L COS. Additionally, the incorporation of activated carbon significantly promoted both the maturation and germination of somatic embryos. In the somatic embryo maturation stage, 1 g/L activated carbon induced 288.67 mature embryos per gram of embryogenic callus, resulting in a total of 1452 embryos. During germination, the application of 4 g/L activated carbon achieved a germination rate of 63%, and the survival rate of somatic embryo-derived seedlings reached 85%. This study not only identifies the optimal conditions for somatic embryogenesis in Pinus elliottii but also establishes an efficient protocol for somatic embryo maturation induction, providing a crucial scientific foundation for the rapid propagation and seedling production of Pinus elliottii.