Real-Time In Vivo Monitoring of Reactive Oxygen Species in Guard Cells

The intra-/intercellular homeostasis of reactive oxygen species (ROS), and especially of superoxides (O₂^.-) and hydrogen peroxide (O₂^.-) participate in signalling cascades which dictate developmental processes and reactions to biotic/abiotic stresses. Polyamine oxidases terminally oxidize/back convert polyamines generating H₂O₂. Recently, an NADPH-oxidase/Polyamine oxidase feedback loop was identified to control oxidative burst under salinity. Thus, the real-time localization/monitoring of ROS in specific cells, such as the guard cells, can be of great interest. Here we present a detailed description of the real-time in vivo monitoring of ROS in the guard cells using H₂O₂^- and O₂^.- specific fluorescing probes, which can be used for studying ROS accumulation generated from any source, including the amine oxidases-dependent pathway, during development and stress.