Miller, Nathan D. , Durham, Tessa L. , Spalding, Edgar .
Effects of Initial Conditions on Arabidopsis Root Gravitropism Determined by Computer-Vision-Based Morphometric Profiling.
Currently, the most common method of measuring root gravitropism involves manual processing of image sequences. The low throughput of manual methods limits the speed at which conditional factors that influence root gravitropism can be investigated. Because an understanding of what factors influence the wild-type response is a prerequisite for understanding the effects of natural and induced genetic variation, an automated, computer-vision based method of quantifying gravitropism was developed. Now, a morphometric profile can be automatically quantified from electronic image series with high spatiotemporal resolution. The goal of this study is to determine in a systematic way how factors such as seed size, seedling age, direction of rotation, initial root length, and growth rate influence the development of gravitropic curvature in the wild type. Currently, approximately 100 seedlings per week are imaged for 10 h at 2 min resolution as they undergo gravitropism. The image stacks along with relevant genetic and conditional information are cataloged in a database. Automatically, the software performs tip tracking, contour isolation, midline extraction, and calculation of tip attack angle, tip trajectory, total angle, spatiotemporal curvature distribution, histogram distributions, and entropy. Vectors consisting of these features are analyzed with standard hierarchical and K-means clustering algorithms. Our preliminary data show correlations between growth rate and spatiotemporal curvature distribution and novel relationships between seedling age and seed size and the rate and location of curvature development. This approach will help make quantitative assessments of the interactions between genotype and environment in the production of the gravitropic phenotype.
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1 - University of Wisconsin - Madison, Departments of Botany and Biomedical Engineering, Madison, WI, 53706
2 - University of Wisconsin - Madison, Department of Botany and Cellular and Molecular Biology Program
3 - University of Wisconsin - Madison, Department of Botany, 430 Lincoln Drive, Madison, WI 53706 U.S.A
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM