Physical Aspects of Fruit Growth : THEORETICAL ANALYSIS OF DISTRIBUTION OF SURFACE GROWTH FORCES IN FRUIT IN RELATION TO CRACKING AND SPLITTING

Abstract

The theory of shells has been applied to some aspects of the physics of fruit growth. Four form and structural attributes are identified which may intensify mechanical stress in the skin of a growing fruit and alter the distribution of that stress. One is a radius-related factor introduced by deviation of shape from that of a sphere and the other three are related to attachment of a fruit to a plant and to provision of a vascular system: core diameter, core tensile strength, and structure of the core/skin interface. The last factor also applies in principle to a hole which may be introduced for example at the style canal. These factors either alone or in combination can cause stresses far in excess of those predicted for a spherical shell of similar volume and wall thickness. They are considered in relation to their effect on fruit morphogenesis and the occurrence of disorders such as rainfall-induced splitting and cracking.