New Methods to Quantify Root Responses to Variable Water or Nutrient Supply

Strategies and protocols for studying root dynamics and architecture are confined by the methodological challenges of studying tissues embedded in an opaque soil matrix. Techniques such as rhizotrons (glass windows), minirhizotrons (acrylic tubing), root-exclusion tubes, and ground penetrating radar have dramatically improved our understanding of root growth.  However, improvement in root sampling methodology must bypass the limitation of highly disruptive root excavation, viewing roots on planar surfaces, and resolution restrictions of bulk-imaging techniques. Recent nondestructive in situ methodologies for studying roots and root systems embedded within a medium currently include MRI, laser, and ultrasound options.  High-resolution X-ray computed tomography (CT) scanning offers a nondestructive option to viewing root systems in both space and time Primary complexities include root organ visualization, due to similarities between the attenuation coefficient of root tissue and organic matter, with most studies to date using large particle substrate types comprised largely of sand and the inverse relationship between root resolution and sampling volume. I will highlight recent advances in nondestructive measurements of the root environment and these technologies can be utilized in questions surrounding precision resource management.