Synchrotron X-Ray Microtomography—New Means to Quantify Root Induced Changes of Rhizosphere Physical Properties

Aravena, Jazmı́n E. and Berli, Markus and Menon, Manoj and Ghezzehei, Teamrat A. and Mandava, Ajay K. and Regentova, Emma E. and Pillai, Natarajan S. and Steude, John and Young, Michael H. and Nico, Peter S. and Tyler, Scott W.

Soil–Water–Root Processes: Advances in Tomography and Imaging, pp. 39-67 , 2013.

Abstract

The rhizosphere, a thin layer of soil surrounding plant roots, plays a dynamic role in the hydrologic cycle by governing plant water and nutrient uptake. Study of rhizosphere soil structure formation due to mechanical processes has been limited by a lack of nondestructive techniques to quantify the dynamic nature of this region. In this chapter, we present recent developments in visualizing how growing roots modify their physical environment by moving soil particles, deforming aggregates and decreasing the amount of inter-aggregate pores while creating hydraulic pathways that connect neighboring soil aggregates using noninvasive, synchrotron X-ray microtomography (XMT). Image-processing tools were applied for quantifying root-induced rhizosphere alterations from XMT grayscale images as well as to transform XMT images into finite element meshes, building a bridge from nondestructive rhizosphere visualization to micromechanical and hydraulic simulations.