Résumé
Arabidopsis thaliana has emerged as a model species for understanding
the basic mechanisms of endosperm development that are conserved in many Angiosperms. In this work, we
focus on the genetic, molecular and cellular studies in Arabidopsis that
have contributed to our current knowledge. Although initially syncytial, the endosperm differentiates several
domains, the origin and function of which will be reviewed. This syncytial phase is followed by a cellular
phase. We discuss the mechanisms controlling transitions between the two major phases. This work also
emphasizes the major role played by endosperm in the control of seed size. Such regulation involves complex
co-ordination with other seed components and epigenetic controls.