plant zygote stage zygote stage (broad) embryo stage EM1 (related) one cell stage (related) Precedes the sporophyte vegetative stage (PO:0007134). Refers to the GO biological process term fertilization (GO:0009566). A sporophyte development stage (PO:0007134) that occurs during the interval between fertilization and the first cell division of the plant zygote (PO:0000423). plant_structure_development_stage GRO:0007168 zygote in Arabidopsis (related) PO:0001097 PO_GIT:399 sporophyte development stage