Changes in cell number and cell size during pineapple (Ananas comosus L.) fruit development and their relationship with fruit size

In mainland China, more than 80% of pineapples (Ananas comosus L.) grown are the cultivar ‘Comte de Paris’. Fruit size is an important commercial trait in crops such as pineapple and it is generally believed that cell number and cell size play an important role during fruit size regulation; however, few cellular biological studies on pineapple fruit development have been conducted. To better understand the regulation of pineapple fruit size, the changes in cell number and cell size during fruit development were analysed. Pineapple cv. ‘Comte de Paris’ fruit were collected every 15 days from 0 to 75 days after the first flower appeared (DAFF), and the flesh of the second (top) and the sixth (base) fruitlets were selected for histological observation. Cell size exhibited a rapid increase up to 60 DAFF, while the cell rapidly proliferated up to 30 DAFF, then slowed down but continued to proliferate. Although grown under identical conditions, ‘Comte de Paris’ pineapples grew to different sizes. The results showed that the cell number, the cell size and the number of fruitlets were correlated with the final fruit size/weight regulation, but that cell number played the most important role.