Differences in the Mobilization of Assimilates of Vitis Vinifera L. Grapevines as Influenced by an Increased Source Strength

¹ Department of Viticulture and Enology, University of California, Davis, California 95616.
² Department of Agronomy and Range Science, University of California, Davis, California 95616.

Assimilate partitioning in whole plants was studied by giving carbon dioxide enrichment (CDE) to grapevines.

The CDE treatments extended from 85-100(%) bloom through fruit maturation. The greater source strength (SoS) in the CDE-treated plants resulted in larger final dry weight of many of the vegetative parts and carbohydrate content of the leaves on vines carrying one or two clusters. The CDE treatments had no significant effect on total leaf area but enhanced fruit yield in the vines carrying two clusters. The CDE treatments significantly increased the rate of shoot growth but had no significant effect on root to shoot ratios and little effect on the (%) distribution of the total plant dry weight among the plant parts.