Cadmium‐induced subcellular accumulation of O 2 ·− and H 2 O 2 in pea leaves

ABSTRACT Cadmium is a toxic metal that produces disturbances in plant antioxidant defences giving rise to oxidative stress. The effect of this metal on H 2 O 2 and O 2 ·− production was studied in leaves from pea plants growth for 2 weeks with 50 µ m Cd, by histochemistry with diaminobenzidine (DAB) and nitroblue tetrazolium (NBT), respectively. The subcellular localization of these reactive oxygen species (ROS) was studied by cytochemistry with CeCl 3 and Mn/DAB staining for H 2 O 2 and O 2 ·− , respectively, followed by electron microscopy observation. In leaves from pea plants grown with 50 µ m CdCl 2 a rise of six times in the H 2 O 2 content took place in comparison with control plants, and the…