Kinematic study of root elongation in Arabidopsis thaliana with a novel image-analysis program

Abstract

The measurement of the spatial profile of root elongation needs to determine matching points between time-lapse images and calculate their displacement. These data have been obtained by laborious manual methods in the past. Some computer-based programs have been developed to improve the measurement, but they require many time-series digital images or sprinkling graphite particles on the root prior to image capture. Here, we have developed GrowthTracer, a new image-analysis program for the kinematic study of root elongation. GrowthTracer employs a multiresolution image matching method with a nonlinear filter called the critical point filter (CPF), which extracts critical points from images at each resolution and can determine precise matching points by analysis of only two intact images, without pre-marking by graphite particles. This program calculates the displacement of each matching point and determines the displacement velocity profile along the medial axis of the root. In addition, a manual input of distinct matching points increases the matching accuracy. We show a successful application of this novel program for the kinematic analysis of root growth in Arabidopsis thaliana.

Quantitative dissection of variations in root growth rate: a matter of cell proliferation or of cell expansion?

“…Nowadays, many tools are available for efficient kinematic analysis ( van der Weele et al , 2003 ; Basu et al , 2007 ; Chavarría-Krauser et al , 2008 ; Wuyts et al , 2011 ; Iwamoto et al , 2013 ; Bastien et al , 2016 ; Yang et al , 2017 ). Various automatic tracking algorithms have enhanced particle image velocimetry techniques, providing high-resolution growth profiles compatible with different kinds of imaging technology.…”

KymoRod: a method for automated kinematic analysis of rod‐shaped plant organs

“…This method is very precise but of limited throughput, in particular for larger organs. Some other methods require contrast‐enhancing manipulations (Basu et al ., ; Hall and Ellis, ), have relatively low throughput (Iwamoto et al ., ) and/or are not well adapted for the analysis of organs with more complex shapes and growth patterns. Here we propose a method that encompasses all the processing steps of the kinematic analysis.…”

3D deformation field in growing plant roots reveals both mechanical and biological responses to axial mechanical forces

“…Early work relied on artificial markers and photographic film to track and quantify tissue deformation. Imaging systems available now have greatly improved with the use of high resolution digital cameras, fluorescence or infrared imaging, and the development of software that recognizes textures from tissues (particle image velocimetry; Basu et al , 2007 ; Iwamoto et al , 2013 ). It is striking that understanding of the biomechanics of root elongation has not progressed at a comparable rate.…”