Do Daily and Seasonal Changes in Non-Structural Carbohydrates in Grapevine Leaves Contribute to Osmotic Adjustment and Regulation of Photosynthesis?

ABSTRACT: Leaves maintain a pool of non-structural carbohydrates (NSC) whose size can vary over hourly and longer timescales. We tested two long-standing hypotheses regarding potential physiological roles of changes in foliar NSC levels. The first is that soluble NSC plays a critical role in osmotic adjustment, with their increase enabling stomatal opening despite daily and seasonal reductions in leaf water potential (Ψ_leaf). The second is that increases in NSC are a sign of excess assimilation relative to sink demand and serve as a signal to downregulate gas exchange. To explore these questions, we monitored the diurnal and seasonal dynamics of gas exchange, Ψ_leaf, osmotic potential, and NSC of irrigated and dehydrated grapevines (Vitis vinifera) through two consecutive growin

SUBMITTER: Perry A 

PROVIDER: S-EPMC12746217 | biostudies-literature | 2026 Jan-Feb

REPOSITORIES: biostudies-literature