Vigorous Root Growth Is a Better Indicator of Early Nutrient Uptake than Root Hair Traits in Spring Wheat Grown under Low Fertility.

Yaosheng Wang,Kristian Thorup-Kristensen,Jakob Magid,Lars Stoumann Jensen

doi:10.3389/fpls.2016.00865

Abstract

A number of root and root hair traits have been proposed as important for nutrient acquisition. However, there is still a need for knowledge on which traits are most important in determining macro- and micronutrient uptake at low soil fertility. This study investigated the variations in root growth vigor and root hair length (RHL) and density (RHD) among spring wheat genotypes and their relationship to nutrient concentrations and uptake during early growth. Six spring wheat genotypes were grown in a soil with low nutrient availability. The root and root hair traits as well as the concentration and content of macro- and micronutrients were identified. A significant genetic variability in root and root hair traits as well as nutrient uptake was found. Fast and early root proliferation and long and dense root hairs enhanced uptake of macro- and micronutrients under low soil nutrient availability. Vigorous root growth, however, was a better indicator of early nutrient acquisition than RHL and RHD. Vigorous root growth and long and dense root hairs ensured efficient acquisition of macro- and micronutrients during early growth and a high root length to shoot dry matter ratio favored high macronutrient concentrations in the shoots, which is assumed to be important for later plant development.

Highlights

Nutrient availability is the primary limitation to nutrient uptake and crop productivity in lowinput and organic agriculture (Mueller et al, 2012)
The content of most macro- and micronutrients was significantly positively and linearly correlated with both root length and surface area (Table 4), and the linear correlation coefficients were higher than those between root hair traits and nutrient content, indicating that vigorous root growth was a better indicator than root hair traits of early nutrient uptake in spring wheat plants grown at low soil fertility
Our study showed that there were significant positive genetic correlations between root and root hair traits and nutrient content, indicating functional links between root traits and nutrient uptake, and showing that selection for improved root traits during early growth may be possibly be employed for breeding of nutrient efficient spring wheat genotypes for low-input and organic agriculture

Summary

Introduction

Nutrient availability is the primary limitation to nutrient uptake and crop productivity in lowinput and organic agriculture (Mueller et al, 2012). It has been suggested that the development of genotypes with appropriate root traits might increase crop yields on infertile soils (Lynch, 2007, 2011; Hawkesford, 2011), and modern cultivars that were bred for the conventional high-input sector with selection in conventional breeding programmes lack important traits required under low-input and organic production conditions (Van Bueren et al, 2002; Murphy et al, 2007; Wolfe et al, 2008). Limitations may yet be imposed on nutrient import in organic farming systems, as exemplified by the plan in Denmark to phase out the use of manures and crop residues from conventional farms (Oelofse et al, 2013), and may be expected to exacerbate the challenge for adequate plant nutrition. There is an interest in elucidating the variability between genotypes of spring wheat in their efficiency in utilizing soil with lower fertility

Objectives

Methods

Results

Discussion

Conclusion