Exogenous gibberellic acid increases the fruit weight of ‘Comte de Paris’ pineapple by enlarging flesh cells without negative effects on fruit quality

Abstract

In mainland China, the most popular pineapple cultivar is ‘Comte de Paris’. Gibberellic acids have been widely applied to enhance fruit growth in various species. To evaluate the effect of gibberellic acid (GA3) on ‘Comte de Paris’ pineapple production and quality, pineapple fruits were sprayed with GA3 at concentrations of 5, 20, 50, or 100 mg l−1 at both 0 and 15 days after flowering (DAF). Fruits were sampled every 15 days from 0 to 60 DAF (maturation) for flow cytometric analysis and histological observation. The results showed that the treatments with the three highest concentrations of GA3 significantly increased fruit weight, and the most effective concentration was 50 mg l−1 GA3, which increased the flesh weight by 20.3% compared to the control. Although treatment with GA3 had little effect on the total soluble solids and fruit juice pH, it increased the vitamin C content. Although flow cytometric analysis showed that the 50 mg l−1 GA3 treatment had only a slight impact on the number of S phase cells, histological observations indicated that the increase of fruit volume and flesh weight under this GA3 treatment was not due to the increase of cell number but a result of the increase of cell area in the fruit flesh.