Development of the Structure of the Normal, Smooth Cuticle of the Apple “Golden Delicious”

Abstract

Theepidermal and cuticular layers of the apple "Golden Delicious" during growth were studied electronmicroscopically with special reference to the cutin containing layer.The structure of the cuticle does not change essentially during the increase in thickness of thecuticle. A fibrillar structure of electron dense material occurs in the cuticle, most clearly in the young apple or in older stages when the wax is extracted. The cutinous substance expands inwardly during growth and in the full-grown stage the epidermal cells can be surrounded with cutinousmaterial. Below a damaged cuticle a very strong cutinization has been observed.

Development of the Structure of the Russeted Apple Skin

“…Note that the suberin lamellae sometimes appear to end in globules (arrow a). around also occurs normally, but much more towards the full-grown stage (DE VRIES 1968). The cells beneath the cuticular epithelium divide and form the periderm.…”

“…The cuticular constituents released pinocytotically by the cell (see 3.3.4.) become located within the cuticles, which are separated from the cells by a layer of cellulose (DE VRIES 1968). The suberin constituents synthesized by a smooth plasmalemma become located next to this membrane.…”

“…Both the globules and the hexagons have a diameter of 600-900 A. The hexagonal structure found in the cuticles of smooth apples varies in diameter from 400-2600 A (DE VRIES 1968).…”

“…Techniques of fixation, postfixation with 2 % OS04 solution, sectioning, and staining for electron microscopy have been described previously (DE VRIES 1968). All the sections were stained with lead citrate.…”

“…The work described in this paper is a continuation of the investigation on the fine structure of the apple cuticle (DE VRIES 1968). It is extended to the russeted cuticle of "Golden Delicious".…”