Recovering Root System Traits Using Image Analysis Exemplified by Two-Dimensional Neutron Radiography Images of Lupine      

Abstract

Root system traits are important in view of current challenges such as sustainable crop production with reduced fertilizer input or in resource-limited environments. We present a novel approach for recovering root architectural parameters based on imageanalysis techniques. It is based on a graph representation of the segmented and skeletonized image of the root system, where individual roots are tracked in a fully automated way. Using a dynamic root architecture model for deciding whether a specific path in the graph is likely to represent a root helps to distinguish root overlaps from branches and favors the analysis of root development over a sequence of images. After the root tracking step, global traits such as topological characteristics as well as root architectural parameters are computed. Analysis of neutron radiographic root system images of lupine (Lupinus albus) grown in mesocosms filled with sandy soil results in a set of root architectural parameters. They are used to simulate the dynamic development of the root system and to compute the corresponding root length densities in the mesocosm. The graph representation of the root system provides global information about connectivity inside the graph. The underlying root growth model helps to determine which path inside the graph is most likely for a given root. This facilitates the systematic investigation of root architectural traits, in particular with respect to the parameterization of dynamic root architecture models.

Plant Water Uptake in Drying Soils

“…For example, RootNav (Pound et al, 2013), SmartRoot (Lobet et al, 2011), RootReader2D (Clark et al, 2013, EZ-Rhizo (Armengaud et al, 2009), and Root System Analyzer (Leitner et al, 2014) were developed for the analysis of two-dimensional root images, while RooTrak (Mairhofer et al, 2013) and RootReader3D (Clark et al, 2011) were designed for the analysis of stereo images. These tools ease the digitizing and analysis of complex root system architecture.…”

It’s Complicated: Intraroot System Variability of Respiration and Morphological Traits in Four Deciduous Tree Species

“…distal to basal) ordering (Uylings et al, 1975). Today, the centrifugal ordering scheme is most commonly used (Fitter, 1996), especially by researchers describing root system development and root phenology of crop species (Chen et al, 2011;Clark et al, 2013;Leitner et al, 2014), but it has also been applied on tree roots (Pregitzer et al, 1997;Majdi et al, 2001). In contrast, ordering in centripetal systems (Strahler, 1957) is initiated at most distal segments, and order number is increased when two root segments of equal order meet (Pregitzer, 2002).…”

L-System model for the growth of arbuscular mycorrhizal fungi, both within and outside of their host roots

“…Root architectural parameters were directly measured by analysing a total of seven previously published [39] images of root systems of M. truncatula with ages ranging from 14 to 18 days, with the software 'RootSystemAnalyzer' [40] (exemplarily shown for one 14-day-old root system in figure 1). It provides the parameters required for the ROOTBOX model [41] from two-dimensional images.…”