Does salinity modify anatomy and biochemistry of Olea europaea L. fruit during ripening?

The effect of salinity on physiology of olive (Olea europaea L.) fruits was studied using a salt-sensitive genotype (Leccino cv.) able to translocate sodium to the aerial part. Plants were treated with 0 and 60 mM NaCl for 49 days starting from the beginning of pit hardening to veraison. The effects of salt exposure were studied classifying olive in two Maturation Groups: MG1olives from green skin to <50% purple skin; MG2olives with purple skin ≥50%. Plants treated with NaCl present a significant reduction of shoot elongation after 35, 42 and 49 days of salt treatment (15%, 18% and 24%, respectively). Na accumulation occurs in fruit flesh depending on the MG: 559 mg kg−1in MG1and 397 mg kg−1in MG2. In general, NaCl does not negatively affect fruit yield parameters while induce an increment of total phenols (58%) and DPPH scavenging activity (15%) in MG1in comparison with control. Cryo-SEM observations of freeze-fractured fruits revealed that salt treatment induce an increment of cells area and a thickening of cuticle, epidermis, hypodermis and outer mesocarp, that could be considered useful to protect fruits against other biotic and abiotic stress.