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INVESTIGATOR: Topp, C.

PERFORMING INSTITUTION:
DUKE UNIVERSITY
BOX 90340 PHYTOTRON BUILDING
DURHAM, NORTH CAROLINA 27708

A MULTIDIMENSIONAL IMAGING PLATFORM TO ANALYZE CROP ROOT SYSTEM DYNAMICS IN RESPONSE TO CHANGING ENVIRONMENTS

NON-TECHNICAL SUMMARY: The health and productivity of crop plants depend on their root systems to extract water and nutrients from the soil. The arrangement of a plant's roots in the soil determines its ability to efficiently extract these resources, especially in changing environments. For example, root systems that grow deeply into the soil are less susceptible to periods of drought, because they can access deep-water resources that shallow root systems can't. However, since nutrients are most abundant in the topsoil, plants with shallow root systems have a resource advantage when water is abundant. The ideal root system would be able to exploit both scenarios. However, we know very little about the particulars of how crop root systems develop and function in different environmental scenarios. The longstanding problem of visualizing root systems can be surmounted by growing plants in an environment that light can penetrate. In this study, we will use a clear gel, supplemented with nutrients of various concentrations, in glass jars. The jars sit on a turntable with a strong light source behind it and a camera in front. As the turntable spins around 360 degrees, the camera snaps pictures. From this set of images, we can make 3-dimensional computer models that accurately represent living root systems. By imaging the growing roots day after day, we can understand how roots grow on a fine-scale. By changing the nutrients and other environmental conditions, we will begin to understand how the environment affects root growth and function.

OBJECTIVES: The overarching goal of this project is to understand how the root systems of crop plants develop, particularly in response to environmental pressures. Specifically, we will study living root systems of several maize varieties that were chosen for particular agronomic traits such as increased planting density and high seed-protein content. These varieties will be subjected to nutrient rich, nutrient poor, localized nutrient, as well as crowded growth conditions to reflect prevalent agricultural stresses. We will study the changes in root system development of each of these varieties as functions of their traits. If similar changes occur among all varieties, then we will be able to characterize shared growth responses to environmental stimuli. If changes in growth responses differ, we will begin to understand key relationships between genotype and the environment. Either outcome is expected to bear on the design and breeding of crop varieties robust to environmental change.