Ultrastructure of the cell walls of Bigarreau Burlat cherries of different textures during ripening

The changes in texture of fruits during ripening are linked to cell wall degradation involving synthesis and degradation of polymers. An increase in pectin solubility leads to cell sliding and an elastic aspect of tissues. The biochemical cell wall process differs between soft and crisp fruits originating from a same cultivar but cultivated under different agroclimatic conditions. Although the proportions of cell wall material are similar, the composition and structure of the two cell walls are very different at maturity. A solubilization of the middle lamella and a restructuration of the primary cell walls arising from the cells separation is observed in crisp fruits. In contrast, the middle lamella of the soft fruits is better preserved and the primary cell walls are thin and show degradation bags delimited by residual membrane formations. In addition, the macroendocytosis process by endosome individualization is more important in soft fruits. In conclusion, the fruit texture depends on the extent of the links between cell wall polymers.