What is the effect of drought on grapevine sweetness?
Grapevines growing under severe summer stress experience a significantdecline in productivity, mostly owing to stomatal limitations to photosynthesis. The photosynthetic productivity is limited by the stomatal closure, either in response to a large decrease in leaf water potential or due to an increase in atmospheric vapour pressure deficit. The active accumulation of soluble sugars and other low molecular compounds is responsible for lower osmotic potential, allowing the cell turgor maintained as much as possible, with positive values during such drought conditions. Therefore grapevine could be even more sweet.