General overview of maize embryogenesis until the Leaf1 stage. (A) Proembryo stage. After fertilization, the zygote undergoes asymmetric cell division to form a small apical cell and a larger basal cell, which develop into the embryo proper and suspensor, respectively. (B) Transition stage. The embryo proper cells differentiate into a shoot apical meristem (SAM) on the embryo's germinal face and the scutellum on the abgerminal side. (C) Coleoptilar stage. The coleoptile initiates above the SAM adjacent to the scutellum. (D) Leaf1 stage. The first leaf primordium initiates from the SAM. Cells below the SAM differentiate into the hypocotyl and root apex. Vasculature tissue becomes histologically visible in the scutellum. The figure was adapted with permission from Wu et al. (2024) under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.