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Grape berry position affects the diurnal dynamics of its metabolic profile
Author(s) -
Reshef Noam,
Fait Aaron,
Agam Nurit
Publication year - 2019
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.13522
Subject(s) - berry , position (finance) , dynamics (music) , biology , horticulture , physics , finance , acoustics , economics
Solar irradiance and air temperature are characterized by dramatic circadian fluctuations and are known to significantly modulate fruit composition. To date, it remains unclear whether the abrupt, yet predictive, diurnal changes in radiation and temperature prompt direct metabolic turn‐over in the fruit. We assessed the role of fruit insolation, air temperature, and source‐tissue CO 2 assimilation in the diurnal compositional changes in ripening grape berries. This was performed by comparing the diurnal changes in metabolite profiles of berries positioned such that they experienced (a) contrasting diurnal solar irradiance patterns, and (b) similar irradiance but contrasting diurnal CO 2 assimilation patterns of adjacent leaves. Grape carbon levels increased during the morning and decreased thereafter. Sucrose levels decreased throughout the day and were correlated with air temperature, but not with the diurnal pattern of leaf CO 2 assimilation. Tight correlation between sucrose and glucose‐6‐phosphate indicated the involvement of photorespiration/glycolysis in sucrose depletion. Amino acids, polyamines, and phenylpropanoids fluctuated diurnally, and were highly responsive to the diurnal insolation pattern of the fruit. Our results fill the knowledge gap regarding the circadian pattern of source‐sink assimilate‐translocation in grapevine. In addition, they suggest that short‐term direct solar exposure of the fruit impacts both its diurnal and nocturnal metabolism.