Figure 1.

Maize silks and their normal function. (A) Maize silks emerging on a young cob. (B) Initial pollen entry onto a hair (trichome) of an individual silk: A pollen grain lands on the exposed silk tissue, from which a pollen tube penetrates the silk channel. Silk hairs, or trichomes, help to guide the pollen into the silks. (C) The exit of the sperm nuclei from the pollen tube-silk complex into the ovule leading to double fertilization: The pollen tube reaches the base of the silk, transporting the two sperm cells to their destination in the ovule. The pollen tube is received by the synergid cell within the ovule. One sperm cell will fertilize the egg cell, while the other will fertilize the central cell.