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Onion Leaf Desiccation Processes and Implications for Skin Quality

conference contribution
posted on 2023-05-23, 07:41 authored by Alistair GracieAlistair Gracie, Boersma, M, Rowan SmithRowan Smith, Brown, P, Dennis, J
Although onion skins play an important role in the life of an onion their development is poorly understood. The skins not only protect the onion bulb from disease and moisture loss but are fundamental to a customer’s perception of bulb quality. This study has increased the understanding of leaf desiccation and the formation of skins. A detailed phenological study across 32 commercial crops ('Creamgold') revealed that the scale of the 6th true leaf was the most common tissue to form the outermost entire skin on the onion bulb. A positive correlation was recorded between bulb diameter and the leaf number (where leaf 1 is the first true leaf) that formed the most-outer skin on the bulb. Skins that are forming but that are not yet completely dry are highly extensible which appears to enable them to withstand the rapid radial expansion of the bulb. Skin tensile strength was positively correlated with skin thickness and skin specific dry weight. Skin specific dry weight was higher in skins that developed from younger leaves, largely due to a higher number of cells in the cross sectional plane. It was posited that conditions that impair early leaf development, and limit the number of cells in the leaf, and therefore the amount of structural tissue in the scale, are responsible for skins that are easily torn and dislodged during handling operations. The importance on the timing of the events may explain the lack of consistency in findings associated with agronomic treatments and the variability in skin disorders between crops.

History

Publication title

Acta Horticulturae

Volume

969

Editors

T Wako

Pagination

203-208

ISSN

0567-7572

Department/School

Tasmanian Institute of Agriculture (TIA)

Publisher

International Society for Horticultural Science

Place of publication

Belgium

Event title

IV International Symposium on Edible Alliaceae

Event Venue

Fukuoka, Japan

Date of Event (Start Date)

2012-05-21

Date of Event (End Date)

2012-05-24

Rights statement

Copyright 2012 International Society for Horticultural Science

Repository Status

  • Restricted

Socio-economic Objectives

Field grown vegetable crops

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