Essential for fertility (male and female gametophyte functions and development) (By similarity). Required for the integrity of female gametic mitochondria (By similarity). Involved in embryo apical-basal patterning, and particularly dorsal-ventral patterning, during early embryogenesis, and endosperm free nucleus positioning and development as well as early endosperm development, probably by modulating the expression pattern of related genes (e.g. AL1, MYB3/AL2, CYP78A13/GE, PNH1, HAZ1, MPK6 and OSH1) (By similarity). Has function in triggering of endosperm programmed cell death (PCD) leading to syncytial endosperm cellularization and starchy endosperm cell maturation (By similarity). Implicated in central vacuole dynamics necessary for microspore development leading to pollen production, and for pollen development and germination (By similarity).