CELL CYCLE SYNCHRONY. “Flowering plants show unique cell cycle control in fertilization among eukaryotes; sperm cells of Arabidopsis in G2 phase have been proposed to fuse with the egg cell in G1/S or G2 phase and with the central cell in G2 phase. Different mechanisms of cell cycle arrest and activation might exist.”
http://www.nature.com/articles/ncomms5722?WT.ec_id=NCOMMS-20140829