Deciphering Root Architectural Traits Involved to Cope With Water Deficit in Oat.

Francisco J Canales,Carmen Müller,Elena Prats,Kerstin A Nagel,Nicolas Rispail

doi:10.3389/fpls.2019.01558

Francisco J Canales, Carmen Müller + Show 3 more

Open Access

https://doi.org/10.3389/fpls.2019.01558

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Abstract

Drought tolerance is a complex phenomenon comprising many physiological, biochemical and morphological changes at both aerial and below ground levels. We aim to reveal changes on root morphology that promote drought tolerance in oat in both seedling and adult plants. To this aim, we employed two oat genotypes, previously characterized as susceptible and tolerant to drought. Root phenotyping was carried out on young plants grown either in pots or in rhizotrons under controlled environments, and on adult plants grown in big containers under field conditions. Overall, the tolerant genotype showed an increased root length, branching rate, root surface, and length of fine roots, while coarse to fine ratio decreased as compared with the susceptible genotype. We also observed a high and significant correlation between various morphological root traits within and between experiments, identifying several of them as appropriate markers to identify drought tolerant oat genotypes. Stimulation of fine root growth was one of the most prominent responses to cope with gradual soil water depletion, in both seedlings and adult plants. Although seedling experiments did not exactly match the response of adult plants, they were similarly informative for discriminating between tolerant and susceptible genotypes. This might contribute to easier and faster phenotyping of large amount of plants.

Highlights

Water deficit is among the most important crop constraints, reducing quality, productivity and compromising economic output and food security worldwide (Farooq et al, 2009)
The root is the first organ exposed to the drying soil and the origin of the signals that orchestrate the machinery leading to drought tolerance (Schachtman and Goodger, 2008)
Plant responses to water deficit may vary significantly according to stress duration and intensity, plant species, growth stage and method of application (Chaves et al, 2002; Jaleel et al, 2008)

Summary

Introduction

Water deficit is among the most important crop constraints, reducing quality, productivity and compromising economic output and food security worldwide (Farooq et al, 2009). Extensive research has been performed to elucidate the plant responses to water stress over the last decades Drought tolerance is a highly complex trait and despite the extensive past research efforts, the components contributing to tolerance remain poorly understood to date (Tuberosa et al, 2002). Most research has focused on the impact of water stress on shoot development parameters, such as, leaf area and shoot dry weight, or agronomic traits such as yield whereas root traits have been largely neglected. The root is the first organ exposed to the drying soil and the origin of the signals that orchestrate the machinery leading to drought tolerance (Schachtman and Goodger, 2008). A detailed study of root response to drought is required to understand plant adaptation to water stress

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