Difese antiossidanti in olivo in condizioni di deficit idrico. Antioxidant defences in olive tree during drought stress.

The olive tree (Olea europaea L.) is commonly grown in the Mediterranean basin and is able to resist severe and prolonged drought. The effects of drought stress and water recovery on the activities of superoxide dismutase, catalase, ascorbate peroxidase, guaiacol peroxidase, polyphenol oxidase and lipoxygenase, and on malondialdehyde levels were investigated in two-year-old olive (cv: "Coratina") plants grown in environmental conditions characterized by high temperatures and different irradiance levels and gradually subjected to a controlled water deficit. The results show that the ability of olive tree to increase antioxidant system activity might be an important attribute linked to drought tolerance. The lower expression of the enzymatic antioxidat system in shaded plants with respect to non-shaded plants may be due to a reduced need of activated oxygen species removal. On the contrary, in non shaded plants, higher enzyme activities are required for a better protection against a more pronounced oxidative stress.