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

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.

Comparative Effects of Individual and Consortia Plant Growth Promoting Bacteria on Physiological and Enzymatic Mechanisms to Confer Drought Tolerance in Maize (Zea mays L.)

“…In the present study, the drought-tolerant NK-6654 seedlings maintained higher biomass by the application of bacterial consortia than the individual inoculants (Table 2). The drought tolerance potential of resistant crop varieties is mainly associated to better root architecture for water and minerals uptake compared to the sensitive ones (Canales et al 2019), which could be further enhanced by the inoculation of maize hybrids with bacterial consortia, also reported by Pereira et al (2020).…”

Affordable Phenotyping of Winter Wheat under Field and Controlled Conditions for Drought Tolerance

“…Seedling root traits were earlier shown to correlate well with root traits at the vegetative stage in wheat but not at the reproductive stage [49]. In oats, moderate correlations were observed among root traits in the seedling stage grown in pots and rhizotrons and those in adult plants under field conditions [50]. Root traits are challenging and laborious to study under field conditions, and drought is unpredictable, making it difficult to select deep-rooted genotypes for drought tolerance.…”

Below‐ground competition favors character convergence but not character displacement in root traits

“…Phenotypic diversity in the traits within functional groups can influence how plants explore the soil and acquire nutrientsfor example, the morphology of individual root traits (root morphology) influences uptake efficiency, how components of traits are arranged spatially (root architecture) influences soil exploration and the uptake of specific nutrients plants, and the size of these traits, the volume they take up (root system size) and the distribution of these elements over space can also influence soil exploration and exploitation of key resources (root system topology; Fig. 1) (Lynch & Brown, 2001;Fitter et al, 2002;Ho et al, 2005;Canales et al, 2019;Nguyen & Stangoulis, 2019). Despite the important ecological and functional role of the root system, only a few studies have explicitly investigated the potential that natural selection can lead to the phenotypic evolution of root traits (Ferguson et al, 2016;Colom & Baucom, 2020;Murren et al, 2020), and even fewer have considered the role that below-ground competition may play in the evolution of the root system (Colom & Baucom, 2020).…”