Post harvest diseases fruits and vegetables - Xavier University ...

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Postharvest Diseases of Fruits and Vegetables
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Number of months at 4-7°C prior to treatment
Fig. 15. Assessment of resistance induction in carrot root slices 16 h after
treatment with heat-killed conidia of Botrytis cinerea. The criterion: germ-tube
elongation on the surface of treated (•) and untreated (o) carrot slices. Vertical
bars indicate standard error. (Reproduced from Harding and Heale, 1980 with
permission of Academic Press).
E. WOUND HEALING AND HOST BARRIERS
Pathogen penetration through a wound, cut, scratch or other injury to
the fruit or other plant organs, is a major way for initiating postharvest
disease. However, a fresh fruit, which escaped infection because of a lack
of appropriate spores or the absence of conditions suitable for
germination, may, in many cases, become more resistant to later
infection. In some instances, the reduced sensitivity of a wound to
infection may be related to its natural drjdng. In other cases, some
biochemical changes which take place at the wound area may lead to its
protection.
Mechanically injured fruit is characterized by enhanced respiration
and ethylene evolution ("wound ethylene"). The injured cells lose their
vitality, whereas living cells around the wound are exposed to stress
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