How Is Corn Fertilized?

Flowers

• The male flowers of the corn plant are found on a modified stem called a tassel. The female flowers are wrapped in leaves and first reveal themselves when the silk projects from these leaves, which are called the husk. The silk is actually a stigma, a landing pad for the pollen. Each ovule has its own thread of silk, and a single ear boasts some 750 to 1,000 ovules, each of which has the potential to develop into a kernel of corn.

Pollination

• Like many grasses, corn is wind pollinated. The flowers on the tassel usually begin to shed their pollen about two or three days before the silk emerges from the husks and continue to release pollen for some five to eight days thereafter. Usually pollen shedding occurs between 9 and 11 a.m., although it may happen later in the day if the weather is humid or overcast. The silk is coated in sticky hairs that grab onto wind-borne pollen and hold it tight.

Hand Pollination

• Many gardeners hand-pollinate their corn to ensure successful pollination and fertilization. If you want to give hand pollination a try, start by cutting tassels from the plant, then dust the silks with pollen from the tassel, using it a little like a wand. Dust the silk thoroughly to ensure all the ovules will be fertilized. If you're having trouble spotting the tassels, look for a small branched structure on the plant and touch it lightly with your fingers; you should see a coating of pale yellow dust. This is what corn pollen looks like.

Fertilization

• Once it's landed on the silk, the corn pollen develops a pollen tube, a long hollow structure running through one of the threads in the silk. Next, two sperm cells make their way down the silk. One sperm cell fuses with an egg cell -- much in the same way that sperm and egg fuse in humans. The other sperm cell fuses with two nuclei called polar nuclei, giving rise to what will later become the endosperm. Endosperm and egg will later develop into a kernel of corn.