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

FREEDOM PALESTINE FREEDOM PALESTINE FREEDOM PALESTINE
Physiological and Biochemical Changes 95
activity and ethylene evolution in citrus fruits (Cohen et al., 1978). When
we compare the effects of different fungi on a certain fruit, e.g., lemon
(Schiffmann-Nadel, 1974), we see that the greatest enhancements, both of
ethylene evolution and respiration, are caused by P. digitatum, followed by
P. italicum, Diplodia natalensis and Geotrichum candidum. Much less
enhancement is caused by the fungi Fusarium moniliforme and Alternaria
citri (Figs. 18, 19). In general, a correlation was found between respiration
and ethylene levels, on the one hand, and the rate of fungal development
on the fruit, on the other hand. Thus, fungi with short incubation periods
and rapid growth cause greater increases in the levels of ethylene and CO2
evolution than those characterized by slow development.
Acceleration of the respiratory activity, ethylene evolution, or both,
has also been found in infected climacteric fruits, e.g., peaches infected
by Monilinia fructicola (Hall, R., 1967); tomatoes infected by Rhizopus
stolonifer, Botrytis cinerea and G. candidum (Barkai-Golan and
Kopeliovitch, 1983; Barkai-Golan et al., 1989b); and bananas, mangoes
O
o
E
.0
v.*
(0
0
a:
250
200 -+-
150 -+-
100 -4-
4 8 12 16 20 30
Days after inoculation
Fig. 18. Respiration rate of green lemon fruit inoculated with postharvest fungi.
(Reproduced from Schiffmann-Nadel, 1974).
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