Acclimation to Drought Stress Enhances Oxidative Stress Tolerance in Solanum lycopersicum L. Fruits

A moderate water deficit stress (S1) applied 10 days after anthesis was found to induce acclimation to a subsequent more severe drought stress (S2) in Solanum lycopersicum L.. When plants were pretreated with S1, and then subjected to S2, fruit water status remained similar to controls. In contrast, S2 induced a decrease in both parameters of water status and diameter of fruits from non-acclimated (NA) plants. Following severe water stress, SOD, CAT and GR activities increased in NA fruits while APX and GR activities decreased in acclimated ones. On the other hand, membrane injury and H2O2 level increased in NA fruits submitted to S2. These results suggest that growing tomato fruits can acclimate to a moderate water deficit stress which moreover improves their ability to survive a more severe stress in the future with the development of less oxidative damage to fruits cells as indicated by MDA content. _____________________________________________________________________________________________________________