Dynamics of bud metabolites during dormancy in sweet cherry genotypes with contrasted chilling requirements

Bud dormancy is a mechanism enabling temperate fruit trees to survive over winter's unfavorable conditions. Buds need a certain amount of chilling temperatures, called chilling requirements, for flowering. Global warming may affect the satisfaction of the chilling requirements and thus directly the yield. The evaluation of endodormancy (true dormancy) release with current methods is plant material consuming, and not attuned between teams. Moreover, the physiological mechanisms taking place during bud dormancy are still poorly known. In order to find biochemical markers for different phases of dormancy and to deepen the knowledge of the events during the dormancy period, we quantified several key metabolites of sweet cherry floral buds throughout dormancy, from summer growth to spring flowering, in two genotypes contrasted regarding their chilling requirements: 'Saint Georges' and 'Burlat'. Results show a temporal lag in the dynamics of accumulation of these metabolites and good correlations with phases of dormancy. Moreover, global accumulation of sugars indicates a weak catabolism of the buds during endodormancy, and a sharp shift to high catabolism upon the endodormancy release period.