Root-root interactions significantly impact the formation of architectural root phenotypes, yet are poorly understood. Phenotype formation is impacted by sensing of soil resources and exudates of neighboring plants (Nord et al., 2011; Wang et al., 2021), which motivates the need to accurately quantify this phenomenon into its underlying causes. Currently, we are developing a complete experimental system for root-root interactions. A mesh frame has been designed to support the growth of two mature plant root systems. The frame is inserted into a large mesocosm, filled with a sand/soil mixture, and two plants are grown. To harvest, the mesocosm is disassembled and the sand/soil is gently washed away. Root systems are left suspended in the mesh and using a Canon EOS Rebel T5, ~500 total photos are taken at 10 different angles ranging from below to above the roots, 360° around the frame. DIRT/3D is used to construct 3D models and extract data from individual root systems. We are in the process of improving our data extraction methods to include spatial traits relative to the two root systems. To do so, we dye the root systems right before harvesting. The difference in coloration allows the use of a deep learning model based on U-net architecture to perform image segmentation and separate roots in the 3D models. Our next step is to run a larger experiment with 10 mesh frames. This will provide statistical significance for trait identification and adaptation of DIRT/3D for root-root interaction data extraction and analysis.

Quantifying phenotypes of root-root interactions would allow a greater understanding of how plants react to belowground competition through plasticity of architectural traits. Past research has shown that plants will over proliferate roots in the presence of competition, leaving less resources to allocate above ground, negatively impacting shoot growth and yields [1]. Further evidence highlights plants may recognize kin and non-kin relationships, responding by avoiding competing with close relatives and instead allocating root mass closer to non-kin neighbors [2]. In an attempt to visualize and quantify root architecture plasticity involved in these root-root interactions, we developed a modified mesocosm system. Within the mesocosm box common bean seeds were germinated 10 inches apart from each other. Mesh screens were placed on either side of each bean, in order to capture root growth towards each other and/or away from each other. Two treatments were involved, with mesocosms grown with either kin or non-kin plants. Plants will be harvested at the 6-week mark, when the root archetype will be developed and prominent. During harvesting one side of the mesocosm box will be removed and the soil will be washed away. We will quantify the degree of root competition by counting the number of roots passing the mesh screen. All general 2D root traits will be measured in DIRT2D. This experiment will shine light on an understudied section of crop science and will allow farmers and researchers a better understanding of an otherwise unseen phenomena.

William LaVoy1 , Limeng Xie1, Suxing Liu1, Alexander Bucksch1231Department of Plant Biology, University of Georgia, Athens, GA 306022Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 306023Institute of Bioinformatics, University of Georgia, Athens, GA 30602