The Effect of Limiting Leaf Area During Stage I of Berry Growth on Development and Composition of Berries of Vitis vinifera L. cv. Cabernet Sauvignon

Abstract

The effects of limiting leaf area during the early stages of berry development on further berry growth and composition were investigated. Leaves were removed from fruiting grapevine cuttings (Vitis vinifera L., cv. Cabernet Sauvignon) just after fruit set giving a leaf area per berry of 1 cm² and 3.3 cm² for the treated and the control plants, respectively. Photosynthetic compensation did not occur at this stage. During the period of slow berry growth, the source capacities were restored by the development of new leaves. Consequently, at veraison, the leaf area per plant was similar for both groups of plants. Leaf removal just after fruit set strongly reduced berry growth. At the end of the first growth period, the berry fresh weight of the treated plants was half that of the control plants. The pericarp cell size was very much affected. Leaf area restoration allowed the treated berries to grow at the same relative growth rate as control berries during stage III. However growth rate compensation did not occur, and berry size at maturity was proportional to the size before veraison. Limiting leaf area shortened the first active growth period of the berries and delayed the onset of ripening. Berry composition was also affected by leaf removal. Osmolarity, titratable acidity, malic acid and soluble sugar concentration in the juice were significantly reduced on the treated plants at the end of the first growth period. Tartaric acid concentration was unaffected. At maturity, the organic acids and fructose concentrations were higher for the LS berries. Osmolarity, titratable acidity, and hexose accumulation rate were unaffected. We conclude that an early assimilate limitation affects the final berry size, but does not reduce the potential growth and accumulation capacities of small berries during ripening.