Abstract

Perennial deciduous trees such as Prunus avium undergo seasonal transitions, culminating in bud dormancy establishment that involves coordinated physiological and metabolic adjustments. Dormancy monitoring in orchard systems still relies primarily on temperature-based models and forcing assays, which rarely incorporate physiological or biochemical indicators. Here, we tested whether seasonal metabolic dynamics associated with dormancy progression differ between sweet cherry genotypes and whether these physiological differences are reflected in canopy-scale vegetation indices derived from satellite observations. Field measurements were conducted in two genotypes with contrasting chilling behavior ('Regina' and '210') during the transition from vegetative growth to dormancy. Leaf gas exchange and chlorophyll fluorescence were monitored across the season, polar metabolites in floral buds were profiled by gas chromatography-mass spectrometry, and satellite-derived vegetation indices were used to characterize canopy dynamics. Dormancy progression was associated with declines in CO2 assimilation, transpiration, PSII photochemical efficiency, and electron transport rate, accompanied by increases in intercellular CO2 concentration and non-regulated energy dissipation. Metabolomic analysis revealed that genotype explained a larger proportion of metabolite variation than dormancy stage (PERMANOVA R2 = 0.483, p = 0.001), while principal component analysis accounted for 79.7% of total variance. Fructose showed the strongest genotype difference during paradormancy I, corresponding to an approximately 9.5-fold increase in 'Regina'. Pathway enrichment analysis highlighted starch and sucrose metabolism and pyruvate metabolism as the most represented pathways during dormancy progression. Satellite-derived vegetation indices captured seasonal canopy decline and were significantly associated with several physiological variables. These results provide an integrated description of physiological and metabolic adjustments during dormancy establishment in sweet cherry and highlight the potential of combining metabolomics, plant physiology, and open-access satellite observations to monitor phenological transitions in orchard systems at scalable spatial and temporal resolutions.