Why does embryo development in Ginkgo biloba finish in the spring after pollination?

The reproductive cycle of Ginkgo biloba is a prolonged process that spans approximately 14 months to ensure the successful development of seeds. While pollination and the development of the sexual, or gametophytic, phase occur during the first year—typically between April and September—the completion of embryo development is delayed until the following spring.1

This timing is a result of the plant's specific reproductive strategy: fertilization often takes place only after the ovules have fallen from the trees, which can occur three or four months after the initial pollination. Following fertilization, the growth of the embryo (embryogenesis) may begin shortly thereafter, but it continues to develop even after the seeds have fallen to the ground. Consequently, the maturation of the embryo into a new sporophyte generation is not finalized until the spring of the year following pollination.21