This work presents new knowledge about the systematic effects
of Al2O3 nanoparticles on a model plant cell culture, a suspension
culture of tobacco BY-2 cells. Al2O3 nanoparticles exhibited toxicity
that was closely connected with the generation of reactive oxygen
and nitrogen species in both concentration- and time-dependent
ways. The generation of ROS and RNS is involved in the processes
of programmed cell death. We observed not only cytological signs
of PCD (shrinkage of cytoplasm, changes in the nuclear architecture,
fragmentation of the DNA and the formation of apoptic-like bodies),
but also changes in the integrity of plasma membrane, changes in
the mitochondrial potential and the initiation of PCD mechanisms
executed by caspase-like proteins. Our work represents the first
study of the toxicity of Al2O3 nanoparticles and demonstrates the
induction of PCD in a plant cell model.