Double fertilization: One of the two sperm nuclei fertilizes the egg cell; the other fertilizes the central cell

Pollen tube discharges sperm into one of the synergids

A typical picture of the double fertilization process. The pollen tube (pt) enters through the micropyle, one of the synergids (s) discharges its contents. Then the sperm nuclei traverse the synergid, one enters the egg cell (e) and the other enters the central cell (cc). Thereafter, their nuclei (unlabeled arrows) fuse with the egg nucleus (yellow) and the polar nuclei (red).

ii = inner integument; n = nucellus

Illustration modified from: Dumas & Mogensen, 1993, The Plant Cell 5: 1337-1348