Crop Production Blog

Brace Yourself

Many corn stalks will send extra roots from a node or nodes above the soil surface. The question of what they actually do for the plant is a question that has never been answered. (DTN photo by Pamela Smith)

DECATUR, Ill. (DTN) -- Brace roots are the Rodney Dangerfields of the cornfield.

The funky, finger-like protrusions have been around since the teosinte, the grass ancestor of maize. But until now, they have never gained enough respect to be studied. Plant biologist Erin Sparks is currently digging into the question in her University of Delaware laboratory.

"People that work on roots think they're not roots because they are above ground, and those that research shoots think they are roots -- so they've sort of been lost in this middle ground," said Sparks.

Most of what we know about brace roots is anecdotal through stories and farmer observation. They were likely named for the belief they help anchor the plant, she said.

However, since some brace roots never reach the ground, some scientists are now questioning their value. Are they simply a burden on the plant -- a carbon expense bringing no return? Or do they really prop the plant up and help prevent lodging?

Sparks is looking at the stability question much as a civil engineer might view a bridge. She's measuring different shapes and sizes of the secondary roots and using computer models to see how or if they provide structural support.

She also believes there may be environmental reasons brace roots begin to show up around the V-8 growth stage.

The corn plant's vascular system is made up of two major vessels: the xylem and the phloem. The xylem is responsible for the transport of soil water and nutrients from the roots to the shoots. The phloem is responsible for the transport of sugar (food) from the leaves to the rest of the plant.

"In corn, there are multiple xylem elements. Mature maize roots have about six of these elements. But brace roots can have to up to 48 xylem elements. So the theoretical capacity to move water through a brace root is exponentially higher than through a primary root," she noted. "So it could be they are important for nutrient and water acquisition when the underground root system isn't getting what it needs."

Just brace yourself to be disappointed if you are a firm believer in the attributes of these supplementary roots.

"Honestly, the answer is we don't know. My argument is that we've done all this intensive breeding and we still have brace roots, so they probably provide some important function. But it is yet to be determined," she said.

Find more information about the Sparks Lab here:…

Pamela Smith can be reached at

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