P27 - Plant water uptake

Rhizosphere functions in plant water uptake: Mechanistic link between carbon and water fluxes in the plant-soil system


The root architecture of a plant is the result of the tradeoff between maximizing the soil explored for water and nutrients and minimizing the cost of carbon (C) and energy needed for root development and maintenance. Crops such as cereals develop complex root systems consisting of several root types. Given such complexity, it is fundamental to understand why plants develop such complex root systems. What is the contribution of different root types, root segments and rhizosphere properties to water and nutrient uptake, particularly under water deficit conditions? Individual roots have varying contributions to water uptake from the soil; thus, it is vital to understand whether plants promote elongation and production of a particular root type under varying soil conditions (e.g., soil moistures and textures).
The general objective of this project is to link the pattern of C allocation into different root segments (i.e., root type, root age and locations) and their rhizosphere to the functioning of roots in water acquisition from the soil. We will consider different water contents to assess the effect of soil drying, as the major soil physical constraints to plant production, on the spatiotemporal pattern of C allocation across the soil-plant-atmosphere continuum, and root water uptake. The main hypothesis is, that under varying soil conditions (moisture and texture), plants allocate more C to the production and maintenance of individual roots (type and regions) that have greater functionality in water uptake.
We plan to quantify root growth and water flux along root-shoot systems of soil-grown plants using a neutron radiography technique combined with injection of D2O. These results will be combined with modeling of water flow and microscopic cross-sections of roots and shoots to estimate the profile of hydraulic conductivities. In parallel, we will mechanistically quantify C fluxes across the soil-plant-atmosphere continuum using a combination of 13C and 14C labeling experiments.

Link to English scientific abstract

Link to German scientific abstract