Revealing the Environmental Factors That Influence the Leaf Biochemistry and Total Antioxidant Activity of Prunus laurocerasus L.

Understanding the seasonal dynamics of phytochemical composition in evergreen species is crucial for improving ecosystem productivity models and selecting appropriate species for urban landscapes under changing climate conditions. However, knowledge about how light environment, temperature, and precipitation interact to regulate leaf biochemical processes across seasons remains limited. We investigated morphological and biochemical responses of cherry laurel (Prunus laurocerasus L.) grown under contrasting light environments (light-exposed versus shaded) across twelve months, analyzing photosynthetic pigments, antioxidants, osmolytes, and secondary metabolites in relation to environmental variables. Light-exposed leaves exhibited enhanced accumulation of photoprotective compounds, including carotenoids (9.38 mg g−1), xanthophylls (3.60 mg g−1), and flavonoids (0.51 mg g−1), along with superior total antioxidant capacity during spring and autumn. Proline showed bimodal seasonal peaks (93.7 µmol g−1 in August under shade, 71.1 µmol g−1 in July under light), indicating stress responses to both summer heat and winter cold. Multivariate analyses revealed that seasonal variation accounted for 94.9% of total phytochemical variability, with distinct metabolic signatures characterizing winter (high glycine betaine, anthocyanin), spring (high chlorophyll, phenolics), summer (high proline, transient carotenoid peaks), and autumn (maximum antioxidant capacity) periods. We conclude that light environment significantly influences cherry laurel’s seasonal metabolic strategies, with shade-grown plants prioritizing light harvesting efficiency and osmotic adjustment, while light-exposed plants emphasize photoprotection and antioxidant defense. The coordinated regulation of functionally related compounds reveals integrated stress response mechanisms that contribute to cherry laurel’s remarkable environmental plasticity. These quantitative seasonal patterns provide valuable parameters for optimizing cultivation practices, predicting biochemical composition for harvesting purposes, and modeling the ecological performance of this species in variable urban and forest environments under climate change scenarios.