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

•Leccino cultivar was treated from pit hardening to veraison with 60 mM NaCl water.•Na accumulation occurs in fruit flesh depending on the Maturation Group.•PAL and DPPH activity increase in salt treated fruit flesh with <50% purple skin.•Tissues thickening in fruit flesh of salt treated plants was recorded.

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: MG1 olives from green skin to <50% purple skin; MG2 olives 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−1 in MG1 and 397 mg kg−1 in 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 MG1 in 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.