Impact of temperature variability on carbon and nitrogen storage in plum branches

The aim of this study was to investigate the variation of reserves in dormant and bud break branches of local and introduced plum genotypes in Morocco. An ex situ collection of twenty-eight Japanese and European plum cultivars, installed at the INRA experimental field in Taoujdate, Morocco, was examined during the period of 2019–2020 and 2021 to assess their total soluble solids (TSS), soluble sugar (SSC), and amino acid (AAC) content in branches during the two phases of dormancy and bud break. The results showed significant differences between cultivars and years for each characteristic analyzed. During the transition from the two phenological phases monitored, TSS and SSC in the shoots decreased significantly, while AAC increased. The correlation coefficients showed significant differences for each of the traits studied. The correlations highlighted the particular involvement of sugars in the lifting of dormancy and amino acids in bud break and flowering, emphasizing that the correlation between SSC and AAC is negative. This research is of great importance for the expansion of the plum growing area, taking climatic conditions into account, and for contributing to our understanding of the biochemical mechanisms involved in dormancy breaking and flowering.