The tripeptide glutathione plays multiple roles in plant defense and metabolism. As one of the most common antioxidants in plants it can control the redox status and detoxify reactive oxygen species. It can also detoxify heavy metals and xenobiotics. Glutathione is synthesized in two ATP-dependent steps which are restricted to the cytosol and the plastids. Since the glutathione content depends on the development and on the stress defense of plants and influences the metabolism a sufficient supply of glutathione is necessary. Furthermore, differences in glutathione contents in tissues and organelles carry information about the development or stress status of the cell.The present work analyzed the subcellular distribution of glutathione in leaves at different stages of development (older and younger leaves) as well as in different leaf areas (leaf center, leaf apex, leaf base, and leaf edge) of Arabidopsis thaliana. Moreover, cell sizes and compartments were measured and compared to each other. General size differences of cell compartments between different leaf areas and stages of development could be analyzed and documented.To determine the subcellular distribution a method was used which is based on the treatment of ultrathin sectioned with glutathione-anti-serum and gold conjugated secondary antibodies. Subsequently, the density of these particles were analyzed in the different cell compartments by quantitative transmission electron microscopy.As the study shows, the highest glutathione content is present in mitochondria. High levels of glutathione were also found in peroxisomes and in the cytosol. Further, the subcellular distribution of glutathione and the total glutathione content were found to be largely independent of the leaf areas in younger leafs, whereas in older leaves significant differences could be detected. There, the highest content was found in the leaf center and the leaf edge, while the leaf apex had the lowest glutathione content.