Physical Aspects of Fruit Growth: Cuticular Fracture and Fracture Patterns in Relation to Fruit Structure inVitis Vinifera

SummaryThe fine structure of surface fractures in the dermal system or skin of the fruit of the grape cv Sultana is described and assessed in relation to the geometry of the dermal system cells. The observations indicate that the cuticle is less extensible than the underlying epidermal and collenchymal cell walls. Cell to cell adhesion was not a limiting factor and the fractures proceeded directly through the cell walls, pulling them into sheets of rope-like strands. Fracture orientation was not determined by cell geometry and, in spite of marked variation in geometry and wall thickness with site on the surface of the fruit, the dermal system behaved like a membrane of uniform physical properties.