Wednesday, February 17, 2010

Plant Profile: Corn

By Nina Berryman

Corn has received a lot of attention these days with such movies as “King Corn” and Michael Pollan’s book “The Omnivore’s Dilemma.” The main message in these two works is that corn is in a frighteningly large percentage of our foods, whether it is in the form of high fructose corn syrup, or in the bodies of the cows we slaughter for meat. This article however, is not going to be about that. If you haven’t seen or read either of these works, I do strongly recommend them.

Zea mays is in the Poaceae (also known as Gramineae) family, along with almost all other grasses and grains. It originated in tropical America and slowly spread north via Native American trade routes. The broad categories of edible corn are sweet corn, popcorn, and baby corn, seen in fancy restaurants. Baby corn was originally harvested out of necessity in Asia, as a secondary harvest after the larger, primary ears. Royal Chinese families popularized it and now there are specific varieties that produce baby ears. More recent varieties of sweet corn have been developed that have many more times the sugar content than older varieties. The ancestor to all modern corn varieties is a wild plant called teosinte which still grows in Mexico.

Looking at corn is a great way to learn about grain anatomy since the plant is so large. On the top of each plant are the tassels, which are the male flowers of the corn stalk. Each tassel produces pollen. Along the stalk of a corn plant are leaf sheathes branch off, like blade of grass. In the crevice of a leaf and the stalk (an area called the node) grows the ear of corn. One ear of corn is a collection of female flowers. Each flower sends up a silky thread which you see at the top of an ear of corn. Each silk catches a grain of pollen. One pollen grain will travel down the silk, into the protected “inflorescence” of female flowers and fertilize an ovary. This fertilized egg is one kernel of corn! One ear of corn has about 200 to 400 kernals. Kernals can be white, yellow, black, blue, red green and purple.

Sources: Seed to Seed, Suzanne Ashworth

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