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

The effects of limiting leaf area during the early stages of berry dev elopment on further berry growth and composition were investigated. Le aves were removed from fruiting grapevine cuttings (Vitis vinifera L., cv. Cabernet Sauvignon) just after fruit set giving a leaf area per b erry of 1 cm(2) and 3.3 cm(2) 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 re stored by the development of new leaves. Consequently, at veraison, th e leaf area per plant was similar for both groups of plants. Leaf remo val 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 m uch affected. Leaf area restoration allowed the treated berries to gro w at the same relative growth rate as control berries during stage III . However growth rate compensation did not occur, and berry size at ma turity was proportional to the size before veraison. Limiting leaf are a shortened the first active growth period of the berries and delayed the onset of ripening. Berry composition was also affected by leaf rem oval. Osmolarity, titratable acidity, malic acid and soluble sugar con centration in the juice were significantly reduced on the treated plan ts at the end of the first growth period. Tartaric acid concentration was unaffected. At maturity, the organic acids and fructose concentrat ions were higher for the LS berries. Osmolarity, titratable acidity, a nd hexose accumulation rate were unaffected. We conclude that an early assimilate limitation affects the final berry size, but does not redu ce the potential growth and accumulation capacities of small berries d uring ripening.