Root architecture governs plasticity in response to drought

Abstract

Aims Root characteristics are important for predicting plant and ecosystem responses to resource scarcity. Simple, categorical traits for roots could be broadly applied to ecosystem function and restoration experiments, but they need to be evaluated for their role and behaviour under various stresses, including water limitation. We hypothesised that more complex root architectures allow more plastic responses to limited water than do tap roots. Methods We carried out two greenhouse experiments: one with a range of grassland plant species; the other with only species of Asteraceae to test the responsiveness of root architectural classes to location of limited water in the soil column. Using trait screening techniques and X-ray tomography, we measured the plasticity of the roots in response to water location. Results Plasticity of root biomass was lowest in tap rooted species, while fibrous and rhizomatous roots allocated biomass preferentially to where the soil was wettest. X-ray tomography indicated that root morphology was least plastic in rhizomatous species. Conclusions Our results provide a starting point to effective categorisation of plants in terms of rooting architecture that could aid in understanding drought tolerance of grassland species. They also demonstrate the utility of X-ray tomography in root analyses. Electronic supplementary material The online version of this article (10.1007/s11104-018-3824-1) contains supplementary material, which is available to authorized users.

The response of root traits to precipitation change of herbaceous species in temperate steppes

“…These results support our second hypothesis that the response of root traits to water availability was species‐specific and that trait‐dependent adaptation to water availability existed in both manipulated precipitation change experiment at local scale and along the precipitation gradients. In this context, Fry, Evans, Sturrock, Bullock, and Bardgett () reported the different plasticity of root in response to draught among plant species with different root architectures. These findings indicate that different plant species have evolved diverse adaptive strategies to cope with the changing regimes of water availability.…”

Forage legumes for future dry climates: Lower relative biomass losses of minor forage legumes compared to Trifolium repens under conditions of periodic drought stress

“…Mixtures of species show increased plasticity towards drought than respective monocultures, which is mainly attributed to a diversity of rooting depths, N acquisition and root architecture in mixtures (Fry, Evans, Sturrock, Bullock, & Bardgett, ; Hofer et al., ). The present study indicates good performances of M. lupulina and L. corniculatus as alternatives to T. repens when grown in monocultures during the first 1.5 production years.…”

“…Mixtures of species show increased plasticity towards drought than respective monocultures, which is mainly attributed to a diversity of rooting depths, N acquisition and root architecture in mixtures (Fry, Evans, Sturrock, Bullock, & Bardgett, 2018;Hofer et al, 2016).…”

Drought-Tolerant Barley: II. Root Tip characteristics in Emerging Roots

“…Although the impact of developing drought tolerant crops is a key strategy, the underlying mechanisms that can guide breeding efforts remain elusive [26,27]. Root architecture including root hair development plays a critical role in overall water uptake; thus, possible correlation between variation in root hair emergence between drought tolerant ("Solar" and "Solum") and conventional ("Kopious" and "Cochise") varieties necessitates of future assessment [28][29][30][31]. The correlation of the higher grain yield of "Solar" under low-irrigation conditions and the hairy root phenotype observed in this study suggests root hairs may play a role in drought tolerance.…”