Climate change–related water and salinity stress in olive trees: Anatomical traits and mitigation approaches

The cultivar ‘Chemlali’ was subjected to both stresses, water salinity and water scarcity, applied at two levels: 6, 12 g l-1 and 50, 25% field capacity respectively. The anatomical changes under stresses in tree leaves, stems and roots and corrections were monitored. 4% of potassium nitrate was added to correct salt stress, and rehydration for water stress. Five treatments were supervised for each stress type, a control, two stress levels and two corresponding corrections. The olive tree seemed to have a developed natural adaptation system to overcome severe stress levels. Nevertheless, the correction used allowed an improvement of its adaptation, despondingly to the type and level of stress, the correction, the organ and the tissue in question. Significant changes in the proportion of olive tissues subjected to the two stresses were noted. This was accentuated by the correction, namely the development of the palisade parenchyma, the narrowing of the spongy tissue in the mesophyll, and the development of liber at the expense of wood in all organs. The development of the palisade parenchyma likely reinforces the photosynthetic system, while the development of the liber indicated increased consumption of the raw sap needed to overcome the stress.