Proembryo A young plant after fertilization but before differentiation into embryo and suspensor tissue.原胚：从受精卵分裂形成2细胞胚开始至胚芽和胚柄等器官分化之前的胚。
CALCIUM DISTRIBUTION IN THE EGG CELL,ZYGOTE AND PROEMBRYO OF LETTUCE (LACTUCA SATIVA L.)莴苣卵细胞、合子与原胚细胞中钙的分布