UD researchers studying corn brace roots to find true purpose
NEWARK, Del. (Feb. 27, 2018) — Roots are essential to a plant’s growth.
But for as much research that’s been done on corn, brace roots, those that start on the plant above ground, haven’t gotten a lot of attention.
In the early stages of a research project at the University of Delaware’s Biotechnology Institute, Dr. Erin Sparks, assistant professor in plant and soil sciences, aims to quantify the benefits brace roots offer corn plants.
Brace roots are commonly thought to aid the plant’s stability and contribute to water and nutrient uptake but to what degree has not been determined.
Sparks said teosinte, a Mexican grass and ancestor of the modern corn plant has brace roots.
For them to survive decades of breeding without actively selecting for them suggests to Sparks that they serve some purpose.
“We have no idea why the plant would use energy doing something like this,” Sparks said. “They’re either linked to something really important or providing an essential function themselves.”
In her research, Sparks is looking at brace roots structurally in how they support the plant, can protect from or mitigate the damage from lodging; and their physiology in the role they play in plant growth.
“The engineer in me wanted to look at how roots had this stabilizing effect,” Sparks said. “I was really interested in this idea of anchorage.”
In the research’s structural component, Sparks and her team have been phenotyping corn roots, digging up mature corn plants, cleaning soil from the root ball and photographed each one — about 200 a year for two years.
The photographs are then run through a software program that takes numerous measurements of the roots including diameter, density, width and angle from the plant to the ground. They’re also testing each brace root’s mechanical properties with tension, compression and bending tests.
“Those properties are going to impact how well the plant is going to handle that stress, say, wind for example,” Sparks said.
Gathering all this data will create a diverse baseline of root characteristics and work toward determining which are better for plant stability. Are more thinner roots better than fewer thicker roots? Is a wider angle better than one more narrow?
“We’re looking at a bunch of bridges and how they’re put together,” Sparks said.
Sparks said the team is expected to have the initial data collection part done this spring and then start integrating it into structural engineering models to determine which of the characteristics contribute the most benefits.
From there, Sparks said they could compare characteristics of commercial varieties to see where they fall on their baseline.
This year, Sparks said they hope to gather exponentially more data using a robot equipped with LiDAR technology to travel up and down rows of corn. LiDAR, or Light Detection and Ranging, is a method of remote sensing that can then be used to make digital three dimensional representations of a target, in this case, brace roots around the bottom of a corn stalk.
“Were going to have massive amounts of data,” Sparks said and added they won’t have to dig up plants which may allow them to collect data in other research trials or production fields.
In the physiology component, Sparks is measuring the brace roots capacity for nutrient and water uptake. Sparks said conventional wisdom among farmers says that brace roots generally appear near the plant’s flowering stage when the plants are most susceptible to nutrient and water deficit.
In greenhouse growing conditions, the team is diverting the brace roots of corn plants into segregated soil from the primary roots to measure the brace roots contribution.
Theoretically, the brace roots could have eight times more capacity to move water and nutrients the plant. In plant vascular systems, the xylem is responsible for moving water and nutrients from the roots.
Primary roots in corn have six to 10 xylem elements were brace roots have up to 48.
“From a research perspective, we don’t yet know if that’s what they actually do,” Sparks said. “We’re still really at the beginning of a lot of this.”
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