Do roots mind the gap?
What happens when roots lose contact to the soil? Do air-filled gaps at the root-soil interface reduce root water uptake? Or do gaps occur after that water vailability is already limited?
A method to monitor gaps between soil and root is described in Carminati et al. 2009.
by A. Carminati in collaboration with D Vetterlein, U Weller, and H-J Vogel (Soil Physics, UFZ Halle)
Unexpected water dynamics in the root zone
Theory says that during transpiration water potential, and consequently water content, should decrease towards roots. But recent experiments with neutron radiography (link psi\neutra) showed that during drying water content increases towards roots. Instead, after irrigation, the soil near roots remains dry! This observations are explained by mucilage exuded by roots. Mucilage is capable of holding large volumes of water, but it takes time to be rewatered. Effects of mucilage on soil-plant water relations are under investigation…
by A. Carminati 2010, 2011
Observations of water fluxes in soil and plants
We developed a method to observe root water uptake and water flow inside roots in-situ.
We used neutron radiography to monitor the distribution of heavy water (D2O) injected in the soil near the roots of a transpiring lupin in soil. Solving the diffusion-convection equation for the D2O concentration in roots, we derived the local root water uptake at different locations of the root system.
By M. Zarebanadkouki
Measurements of root-soil conductivity
We are currently testing the possibility to measure root-rhizosphere-soil conductivity with a root pressure apparatus normally used for roots in nutrient solutions. This project was inspired by Professor Ernst Steudle.
By Y. Kim