1. What’s the difference between corn and maize?

Maize is a more scientific way of referring to corn and the two terms are interchangeable.

2. What’s it like working in the field?

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It’s hard work, but very rewarding. Doing experiments in the field is difficult because of changing variables like temperature, the sun moving throughout the day and soil variation. Variables like that are often controlled in a laboratory system. Getting good results from the field requires a lot of careful monitoring to ensure the results are caused by our experiment (in this case, drought) and not by an outside variable changing. Although field experimentation is difficult, it provides us with information that is really
similar to an average farmer’s field. This allows us to understand and investigate what is happening to the plants in a real world environment. Understanding how these plants function in a field setting allows us to generate better science to help the farmers in the future.

3. What do you do in the lab?

When we study corn roots in the lab, we set the growing conditions very precisely. This precision is important because it allows us to compare results easily. A typical lab experiment involves adding water to potting soil until it reaches the exact wetness we want. Next, we plant seedlings in custom-made pots constructed out of PVC tubes that section off the nodal roots from the rest of the root system. The plants grow in large chambers that control the air temperature, humidity, and light intensity. When the corn is the correct age, we “harvest” by digging up the roots and cutting off the tips of the nodal roots. We analyze the root tips immediately or freeze them for later.

4. What is the significance of nodal roots?

Nodal roots originate from the stem tissue during the early phases of plant development. They are different from the type of root most people might imagine when they think about a plant or tree root, but these roots are key to agricultural success. Trees and other dicotolydenous plant species posses a tap root type root architecture, in which the root system is comprised of a main tap root and lateral roots that originates from it. Grasses such as corn, wheat, and rice have a fibrous root system in which there is no tap root. Instead, the root system is composed of the “embryonic roots,” such as the primary and seminal roots, which originate from the germinating seed.

Grasses also form “adventitious roots” which arise from tissue other the roots. In corn, this involves the nodal root system which originate from the “crown” or below ground stem tissue, and “brace,” or “aerial roots,” which are nodal roots that emerge from the above ground stem and serve to physically anchor the plant to the soil so that wind can’t blow the plant over.

A large reason why nodal roots are instrumental to plant survival is that many grasses, such as mature corn plants, absorb about 70 percent of their water through the nodal roots. This is because nodal roots possess the unique ability to continue growing through very dry and hard soil. Even when other types of roots quit growing, the nodal roots keep on going, pushing through very dry soil that is often hard and compacted. This allows the plant to continue searching for water at lower depths when a drought has rendered the topsoil devoid of moisture.

Another key aspect to nodal roots’ role for plant health is their anchoring ability. If you go out in a cornfield when the plants are mature, you may see what looks like webbing between the ground and the stalk of the plant about a foot above the surface of the ground.

These are a type of nodal roots called the brace roots, which grow through the air and into the soil, serving as an anchor system to prevent lodging. Lodging is a phenomenon in which high winds and dry soils lead the plant to fall over in the field.

5. What’s the difference between drought resistance and drought tolerance?

The terms “drought resistance” and “drought tolerance” describe the strategy a plant employs to cope with the stress caused by lack of water. A drought resistant plant protects its tissues from becoming stressed in the first place. Conversely, a drought tolerant plant becomes stressed, but uses various biological mechanisms to continue to function despite experiencing water stress. The nodal roots of the corn line that we study, FR697, employ
the first strategy and resist becoming stressed under drought.

6. What genes play a role in drought resistance?

We’re not sure yet, so that’s the purpose of our project! We believe that genes that give the plants the ability to grow their roots longer, even during a drought, will be important for drought resistance. Using our Lab-to- Field approach, we hope to identify the specific genes that are important in this process.

7. Why does this research matter?

In two words: Food Security.

Food security refers to both the availability of food and the stability of its prices, enabling the general public the ability to purchase that food. Population growth and crop loss due to environmental factors are two major factors in conflict with food security. The number one environmental factor effecting crop loss in the United States is drought.  Not much is known about how plants internally resist or tolerate drought. With our study, we hope to address those questions, which will help the scientific and agricultural communities develop crops that might reduce losses or maintain yields during future droughts.