Influence of Bioclimatic Stages on Stable Isotope Composition and Fatty Acid Profiles of <i>Pinus halepensis</i> Oils From Tunisia

This study investigates the biochemical and isotopic traits of Pinus halepensis oil across two bioclimatic semi-arid Henchir Naam arboretum and the sub-humid Korbous arboretum. Findings reveal significant differences in proline and sugar concentrations, fatty acid (FA) type, and their isotopic signatures between the two sites, indicating distinct drought adaptation strategies. In Henchir Naam, two variables showed high values and strong correlations, suggesting specific biochemical adaptations to aridity. FA analysis identified oleic, palmitic, and linoleic acids as dominant, with their composition influenced by both site provenance and environmental stress. The δ¹³C isotopic data confirmed higher water stress levels in the semi-arid region. Overall, the results underscore the interaction between genetic factors and environmental conditions in shaping drought resistance in P. halepensis, offering insights for future reforestation and conservation strategies.