Root anatomical phenes predict root penetration ability and biomechanical properties in maize (Zea Mays)

Abstract

HighlightRoot bending, tensile strength, and ability to penetrate hard soil are related to anatomical phenes that are subject to selection in crop breeding programs.

Root Tip Shape Governs Root Elongation Rate under Increased Soil Strength

“…It has been argued that root diameter is a crucial trait for root growth in compacted soil, since thick roots may reduce penetration stress and prevent the buckling of roots (Materechera et al, 1992;Chimungu et al, 2015). In this study, genotypic differences in root diameters (Table I) were not related to root elongation rate (Fig.…”

“…This adjustment of roots to increased soil strength reduces the risk of root buckling and decreases the mechanical stress acting on the root during penetration (Materechera et al, 1992;Kirby and Bengough, 2002;Chimungu et al, 2015). Root thickening in response to increased soil strength has been observed in a wide range of species under field and laboratory conditions and often coincides with increased cortical area (Atwell, 1990a;Materechera et al, 1992;Grzesiak et al, 2013;Siczek et al, 2013;Chen et al, 2014;Hernandez-Ramirez et al, 2014;Colombi and Walter, 2016).…”

“…Root thickening in response to increased soil strength has been observed in a wide range of species under field and laboratory conditions and often coincides with increased cortical area (Atwell, 1990a;Materechera et al, 1992;Grzesiak et al, 2013;Siczek et al, 2013;Chen et al, 2014;Hernandez-Ramirez et al, 2014;Colombi and Walter, 2016). Since root thickening decreases penetration stress and stabilizes roots, thick roots are likely to be an advantage in soils with increased mechanical impedance (Materechera et al, 1992;Kirby and Bengough, 2002;Chimungu et al, 2015). A recent study showed that the genotypic cortical thickness in maize is related to bending strength and, hence, to the risk of root buckling (Chimungu et al, 2015).…”

“…Since root thickening decreases penetration stress and stabilizes roots, thick roots are likely to be an advantage in soils with increased mechanical impedance (Materechera et al, 1992;Kirby and Bengough, 2002;Chimungu et al, 2015). A recent study showed that the genotypic cortical thickness in maize is related to bending strength and, hence, to the risk of root buckling (Chimungu et al, 2015). As a consequence of the increased volume-to-length ratio in thicker roots, plants need to invest more resources into soil exploration when soil strength increases (Atwell, 1990b).…”

Quantitative 3D Analysis of Plant Roots Growing in Soil Using Magnetic Resonance Imaging

“…Results may thus not be directly transferable to plants grown in natural 3D soil environments (Gregory et al, 2003). For example, roots are known to grow faster and thinner when the penetration resistance is low (Bengough et al, 2011;Chimungu et al, 2015). Computed tomography (CT; both x-ray and neutron) has been proposed to overcome the mentioned difficulties with studying roots in natural soil.…”