Aldehyde reductase or aldose reductase for removing free radicals such as hydrogen peroxide in plants during environmental stress conditions by reducing 4-hydroxy-nonenal in the presence of NADPH
Transgenic plant cells, breeding materials, plant parts and plants in which the expression level of the aldose reductase-homologous protein is increased and which show higher resistance against stress conditions of different origin. Also described are DNA molecules and vectors suitable for the expression of aldose reductase-homologous protein and processes for the preparation of plant cells overproducing aldose reductase-homologous protein. The inserts are suitable for reducing damage in crops caused by harmful biotic and abiotic stress conditions and for enhancing harvest prospects.