Structural basis of the rind disorder oleocellosis in Washington navel orange (Citrus sinensis L. Osbeck).
Oleocellosis, a physiological rind disorder of citrus fruit, is an unattractive surface blemish caused by phytotoxic effects of released rind oils. The development of oleocellosis in Washington navel orange (Citrus sinensis L. Osbeck) was examined by following a time sequence of surface symptoms and microscopic rind changes. The two natural causes of oleocellosis were simulated: mechanical damage to the fruit and transfer of rind oil between fruit. Mechanical fruit injury resulted in rupture of the epidermis above oil glands. Released surface oil appeared to infiltrate the rind via the ruptured epidermis resulting in rapid degeneration of cortical, but not epidermal, cell contents. Oil application to the rind surface produced a more severe blemish than did mechanical damage. The oil appeared to diffuse through the cuticle causing degeneration of the contents of all cell layers, including the epidermis. Loss of membrane integrity was detected within 30 min, followed by cell content degeneration and cell collapse. The resulting blemish, characterized by rind collapse and darkening, developed substantially within 3 d and was attributed to the cellular damage.
Knight
TobyG
T
Department of Horticulture, Viticulture and Oenology, Waite Campus, The University of Adelaide, Glen Osmond, South Australia 5064, Australia.
Klieber
Andreas
A
Sedgley
Margaret
M
D032084:Citrus sinensis / Q000737:chemistry / Q000187:drug effects* / Q000648:ultrastructure; D005638:Fruit / Q000737:chemistry / Q000187:drug effects* / Q000648:ultrastructure; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D010938:Plant Oils / Q000378:metabolism / Q000633:toxicity*
D010938:Plant Oils