The Vibrating Probe Technique in the Study of Root Physiology Under Stress

The present chapter introduces the use of a non-invasive vibrating probe technique to study membrane-transport processes in plant roots. Net ion fluxes and changes in the extracellular concentrations of ions (such as H+, Ca2+, K+, Mg2+, Cl , NH4 +, Cu2+) as well as gaseous molecules (such as O2 and NO) and other compounds (IAA) are very important to understand the physiology of plants under stress conditions. Here, we present an overview on the technique, focusing on background theory, main selective electrodes available, and the major outcomes obtained in the study of roots in order to show how in situ and real-time measurements of net ion and gas fluxes from root cells and tissues can provide insights into the functional genomics of plants and will significantly increase our understanding in plant adaptive responses to environmental stresses.