Nature’s miracle: Corn pollination

In recent weeks, the Midwest region of the United States has gone through the critical stage of corn growth known as pollination. Pollination is part of the reproductive stage in a plant. Much of the potential grain yield is determined at this time, with success or failure of pollination impacting the plant’s life. The varying degree of pollination can mean the difference between the plant growing seeds, or simply growing more flowers.

Pollination is an interesting process that is the end result of a symphony of variables working together to get the crop on the dinner table. It begins when each potential kernel (that future bite of popcorn!) finds a bond between the pollen (male sperm cells from anther) and the stigma (the female reproductive part of the flower or, in this case, the silk). When the pollen comes into contact with the stigma, it grows a tube down to the plant’s ovary, and the ovule inside is then fertilized by the pollen grain. It is that fertilized ovule that becomes the kernal.

And speaking of pollen: “Pollen is captured by the silk hairs, or trichomes,” Bob Nielsen, a Purdue University agronomist said in an article on AgFax. “The pollen germinates and develops a tube that penetrates the silk and elongates down the length of the silk, carrying the male genetic material. All that happens within 24 hours. It really is something.”

Nielsen is a corn master; he is known in agricultural circles on the King Corn and Chat n’ Chew Café websites for his understanding of the crop.

To check if pollination has occurred, Nielsen uses the “shake” technique. By making a single lengthwise cut from the base of the ear shoot to the tip, slowly unwrap the husk leaves, being careful not to rip any silks. Gently shake the ear. If fertilized, silks will drop away. If not, they will remain attached.

All is not lost for unfertilized silks, however. “Maybe [the silks] were at the bottom of that mat of silk and took a little longer to get fertilized.”
After the silk emerges, it can be receptive to pollen for about 10 days, although it is less receptive as each day goes on. Most pollination occurs during the first four or five days.

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