Plant embryogenesis.

Land plants are called 'embryophytes' and thus, their collective name is defined by their ability to form embryos. Indeed, embryogenesis is a widespread phenomenon in plants, and much of our diet is composed of embryos (just think of grains, beans or nuts; Figure 1). However, in addition to embryos as a source of nutrition, they are also a fascinating study object. Some of the most fundamental decisions on fate and identity, as well as patterning and morphogenesis, are taken during the first days of plant life. Yet, embryos are diverse in structure and function, and embryogenesis in plants is by no means restricted to the zygote - the product of fertilization. In this Primer, we discuss the adventures of the young plant. We will consider what it means to be a plant embryo and how to become one. We will next highlight how the study of early embryogenesis can reveal principles underlying oriented cell division and developmental pattern formation in plants.