Root anatomy and soil resource capture

Abstract

Background Suboptimal water and nutrient availability are primary constraints in global agriculture. Root anatomy plays key roles in soil resource acquisition. In this article we summarize evidence that root anatomical phenotypes present opportunities for crop breeding. Scope Root anatomical phenotypes influence soil resource acquisition by regulating the metabolic cost of soil exploration, exploitation of the rhizosphere, the penetration of hard soil domains, the axial and radial transport of water, and interactions with soil biota including mycorrhizal fungi, pathogens, insects, and the rhizosphere microbiome. For each of these topics we provide examples of anatomical phenotypes which merit attention as selection targets for crop improvement. Several cross-cutting issues are addressed including the importance of phenotypic plasticity, integrated phenotypes, C sequestration, in silico modeling, and novel methods to phenotype root anatomy including image analysis tools. Conclusions An array of anatomical phenes have substantial importance for the acquisition of water and nutrients. Substantial phenotypic variation exists in crop germplasm. New tools and methods are making it easier to phenotype root anatomy, determine its genetic control, and understand its utility for plant fitness. Root anatomical phenotypes are underutilized yet attractive breeding targets for the development of the efficient, resilient crops urgently needed in global agriculture.

Characterization of Root System Architecture Traits in Diverse Soybean Genotypes Using a Semi-Hydroponic System

“…However, there are limitations in converting phenotypic data from the seedling stage obtained from semi-hydroponic systems to soybean breeding programs. Roots may have specific responses in different growth environments, and phenotypic plasticity is important for searching for soil resources [18]. Therefore, the phenotypic system needs to produce a reliable ranking of root characteristics, and the selection of growth medium needs to be considered carefully.…”

“…Alterations to root growth and RSA are critical adaptive strategies of crops to cope with drought, soil infertility, and other edaphic stresses [16]. Therefore, it is important to screen and breed crop cultivars with better RSA, which can adapt to edaphic stresses and have improved nutrient and water efficiency [17,18]. The identification of RSA conferring efficiencies in resource acquisition and adaptation to edaphic stresses has increased in research and breeding programs [19,20].…”

The Adaptation and Tolerance of Major Cereals and Legumes to Important Abiotic Stresses

“…Variations in root system architecture can be explored for the development of climate-resilient and abiotic stress-tolerant crops by improving water and nutrient use efficiency [ 339 ]. The primary root elongation rate and ABA accumulation under different water conditions have been studied in 12 maize inbred lines to assess the relationship between root growth and hormonal conditions [ 340 ].…”

Longitudinal Pattern of Aerenchyma Formation Using the Ti-Gompertz Model in Rice Adventitious Roots

“…However, the root elongation rate varies with the root diameter and the depth that the root apex penetrates into the impeded soil ( Lynch et al, 2021 ; Takahashi and Pradal, 2021 ). More active growth occurs at the root apex over the mature root zone ( Lynch et al, 2021 ).…”

“…However, the root elongation rate varies with the root diameter and the depth that the root apex penetrates into the impeded soil ( Lynch et al, 2021 ; Takahashi and Pradal, 2021 ). More active growth occurs at the root apex over the mature root zone ( Lynch et al, 2021 ). Previous studies have not considered on the effect of the root length or are restricted to a few lengths when modeling the longitudinal pattern of aerenchyma formation.…”