ABSTRACT
Grape and wine production has played an important part in Western civilization. Leaf age and time during the growing season influence the concentrations of reducing and nonreducing sugars and starch in grape leaves. Other aerial organs of the grapevine contain chlorophyll, indicating the possibility of photosynthetic activity. The metabolism and transport of carbohydrates within the grape leaf are probably similar to those described for other C3 plant species. Seasonal increments in leaf biomass and leaf area per vine are dependent upon vine age and pruning pattern. The permanent structures of the grapevine are the primary sources of reserve carbohydrate for this perennial crop in the absence of shoots. The initial growth of the shoot is dependent upon carbohydrate reserves in the permanent structures of the vine. The production practices used to maximize the quality attributes or yield can have significant effects on source–sink relationships of grapevines.
