Abstract
The rhizosphere, the fraction of soil altered by plant roots, is a dynamic domain that rapidly changes during plant growth. Traditional approaches to quantify root growth patterns are very limited in estimating this transient extent of the rhizosphere. In this paper we advocate the analysis of root growth patterns from the soil perspective. This change of perspective addresses more directly how certain root system architectures facilitate the exploration of soil. For the first time, we propose a parsimonious root distance model with only four parameters which is able to describe root growth patterns throughout all stages in the first 3 weeks of growth of Vicia faba measured with X-ray computed tomography. From these models, which are fitted to the frequency distribution of root distances in soil, it is possible to estimate the rhizosphere volume, i.e., the volume fraction of soil explored by roots, and adapt it to specific interaction distances for water uptake, rhizodeposition, etc. Through 3D time-lapse imaging and image registration it is possible to estimate root age dependent rhizosphere volumes, i.e., volumes specific for certain root age classes. These root distance models are a useful abstraction of complex root growth patterns that provide complementary information on root system architecture unaddressed by traditional root system analysis, which is helpful to constrain dynamic root growth models to achieve more realistic results.
Highlights
Root-soil interactions are an essential part of global matter cycles as all water and nutrients taken up by the plant have to be transported through the rhizosphere (York et al, 2016)
The experimental root distance histograms in the frequent scanning treatments exhibit a clear transition from triangular distributions (4–8 days after planting) to left skewed gamma distributions (12–16 days after planting) (Figure 3a)
We have introduced the mixed triangular-gamma model to describe root distance histograms, i.e., frequency distributions of Euclidean distances from soil to root, at several growth stages of Vicia faba
Summary
Root-soil interactions are an essential part of global matter cycles as all water and nutrients taken up by the plant have to be transported through the rhizosphere (York et al, 2016). Roots have to fulfill a range of different functions at the same time, resulting in the plasticity of the root system, with individual root segments changing their function during ontogeny (Vetterlein and Doussan, 2016; Morris et al, 2017). There is a genotype specific regulation of root development (Atkinson et al, 2014). This program is modified by soil traits like bulk density, soil structure, water distribution or nutrient supply (Drew, 1975; Passioura, 1991; Robinson, 1994; Malamy, 2005; Hodge et al, 2009; Smith and De Smet, 2012; Giehl and von Wiren, 2014)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
