Shown is a transmission electron microscopy image of seedling mesophyll cells from an Arabidopsis thaliana plastid ferrochelatase 2 (fc2) mutant. In this mutant, chloroplasts can accumulate high levels of toxic singlet oxygen, a reactive oxygen species formed during photosynthesis. In these cells, most of the chloroplasts (green organelles) and mitochondria (red organelles) appear healthy. However, the chloroplast in the top left of the image is being selectively degraded and is interacting with the central vacuole (blue). This strategy to degrade singlet oxygen-damaged chloroplasts may be to help a cell avoid any further oxidative damage during photosynthesis.
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