Advances in understanding pre-harvest apple fruit development

Fruit growth can be defined as the irreversible increase in size of a fruit. Growth is the net balance between incoming and outgoing flows in the fruit. Xylem (transporting water and minerals from the roots) and phloem (transporting sucrose, amino acids and other nutrients from leaves) are the main sources for water and dry matter (DM) transportation/accumulation while epidermal transpiration (both from leaves and fruit) is the main cause of water loss (Fishman and Génard, 1998; Rossi et al., 2022). The varying balance among these fluxes determines typical daily fluctuation in fruit size, controlling fruit development, swelling and shrinkage