Carbohydrate changes
GA3 anticipates glucose uptake in the ‘Emperatriz’
seedless berries compared to untreated berries (Fig. 2).
Glucose concentration increased faster in GA3 160 mg
L–1 treated berries, reaching maximum concentration
67 DAA, whereas control berries reached maximum
value 85 DAA. Similar results were obtained for fructose
and sucrose (Fig. 2). Interestingly, peaks for control
berries were of the same magnitude of those for treated
Gibberellic acid and seedless grape berry size 923
Table 2. Effect of increasing GA3 concentrations applied on peduncle and commercial berry characteristics of ‘Emperatriz’
seedless grape at harvest for the three years of experiments
Year
GA3 concentration (mg L–1)
0 40 80 120 160 200 240 320 400
Peduncle
— Length (mm) 2003 6.4a 6.7b 7.2c 7.0c 7.8d 7.1c
2004 7.2a 7.9d 8.0c 7.8c 7.58b 8.3c
2005 6.4a 7.3c 7.0b 7.0b
— Diameter (mm) 2003 1.4a 1.8b 1.7b 2.0c 2.2d 1.8b
2004 1.5a 1.6b 1.8d 1.7cd 1.7bc 1.8d
2005 1.3a 1.7b 1.8bc 1.8c
Berry
— Fresh weight (g) 2003 3.3a 4.2b 4.5c 5.1d 5.8e 5.0d
2004 3.3a 4.3b 5.2d 5.4d 4.7c 4.9c
2005 3.1a 4.1b 4.4c 4.0b
— Length (L; mm) 2003 19.7a 20.6b 21.0b 23.0d 24.5e 22.3c
2004 19.9a 22.1b 23.5c 23.8c 22.2b 23.3c
2005 18.7a 21.0c 21.0c 20.1b
— Diameter (D; mm) 2003 15.7a 17.5b 17.8bc 18.0cd 18.8e 18.3d
2004 15.9a 17.3b 18.3d 18.4d 17.8c 17.8c
2005 15.6a 17.1b 17.5c 17.4bc
— Shape (L/D) 2003 1.26c 1.18a 1.18a 1.28c 1.30d 1.22b
2004 1.25a 1.27ab 1.28abc 1.29bc 1.25a 1.31c
2005 1.20b 1.23c 1.19b 1.16a
GA3 was applied at the onset of cell enlargement stage. Values are the mean of 120 berries and peduncles. Different letters in the
same column indicate significant differences (P ≤ 0.05).