Root hydraulic properties: An exploration of their variability across scales.

Root hydraulic properties are key physiological traits that determine the capacity of root systems to take up water, at a specific evaporative demand. They can strongly vary among species, cultivars or even within the same genotype, but a systematic analysis of their variation across plant functional types (PFTs) is still missing. Here, we reviewed published empirical studies on root hydraulic properties at the segment-, individual root-, or root system scale and determined its variability and the main factors contributing to it.

Hydraulic flux-responsive hormone redistribution determines root branching.

Plant roots exhibit plasticity in their branching patterns to forage efficiently for heterogeneously distributed resources, such as soil water. The xerobranching response represses lateral root formation when roots lose contact with water. Here, we show that xerobranching is regulated by radial movement of the phloem-derived hormone abscisic acid, which disrupts intercellular communication between inner and outer cell layers through plasmodesmata.

Plant water uptake modelling: added value of cross-disciplinary approaches.

In recent years, research interest in plant water uptake strategies has rapidly increased in many disciplines, such as hydrology, plant ecology and ecophysiology. Quantitative modelling approaches to estimate plant water uptake and spatiotemporal dynamics have significantly advanced through different disciplines across scales. Despite this progress, major limitations, for example, predicting plant water uptake under drought or drought impact at large scales, remain.

Exposure to high nitrogen triggered a genotype-dependent modulation of cell and root hydraulics, which can involve aquaporin regulation.

Root nitrogen acquisition has been proposed to be regulated by mass flow, a process by which water flow brings nutrients to the root surface, depending on a concerted regulation of the root hydraulic properties and stomatal conductance. As aquaporins play an important role in regulating transcellular water flow, we aimed at evaluating the short-term effect of high nitrogen (HN) availability on the dynamics of hydraulic parameters at both the root and cell level and the regulation of aquaporins. The effect of short-term HN (8 mM NO ) treatment was investigated on 12 diverse 15-day-old maize genotypes.

How to Define the Appropriate Spatial Resolution of Root Segments When Solving Water Flow in Root System Hydraulic Architectures.

In this chapter, we discuss the issue of balance between spatial resolution and computational efficiency in the context of the R-SWMS model. Based on the equations governing the water fluxes within the model, we propose here an objective and quantitative criterion which can help fix root segment size to both minimize computational load and achieve simulation according to a given accuracy degree.