Abstract
Plant leaves present an intricate array of layers providing a robust barrier against pathogens and abiotic stressors. However, these layers may also constitute an obstacle for the assessment of intracellular processes, especially when using fluorescence microscopy approaches. Current methods for leaf mitochondrial membrane potential determinations have been traditionally performed in thin mesophyll sections, in isolated protoplasts or in fluorescent protein-expressing transgenic plants. This may limit the amount of information obtained about overall mitochondrial morphology in intact leaves. Here, we detail a fast and straightforward protocol to assess changes in leaf mitochondrial membrane potential associated with mitochondrial dysfunction in the model plant Arabidopsis thaliana. This protocol also permits mitochondrial shape, dynamics and polarity assessment in leaves subjected to diverse stress conditions.