Articles
APPLE SCALD DEVELOPMENT AND REGULATION
Article number
857_42
Pages
349 – 358
Language
English
Abstract
We have compared changes in α-farnesene and conjugated trienols, as well as gene expression, in scald-resistant cultivars, e.g., Gala and Braeburn, and in scald-sensitive cultivars, e.g., Granny Smith, Delicious and Law Rome. We also carried out similar comparisons in Granny Smith between controls and treatments that diminish scald symptoms, e.g., low O2 and 1-methylcyclopropene (1-MCP). The data show that the initiation of the C2H4 climacteric plays a crucial role in scald development, since treatments that retard the onset of the climacteric, e.g., low O2 and 1-MCP, also inhibit symptoms of scald development.
Furthermore, if either low O2 or 1-MCP is applied after the initiation of the C2H4 climacteric, their inhibitory effects on scald development decrease.
The treatments that retard the C2H4 climacteric onset also strongly inhibit the rise in
-farnesene and conjugated trienols.
In Granny Smith apples, we studied the effect of temperature on scald development, as well as changes in the content of-farnesene and conjugated trienols.
The data show that, at temperatures above 7°C, scald failed to develop but the rise in-farnesene and conjugated trienols was not affected.
It should be noted that in scald-resistant cultivars stored at 1°C there was an increase in both-farnesene and conjugated trienols, though not as high as in sensitive cultivars.
However, if the auto-oxidation of α-farnesene and trienols is the cause of scald disorder, their levels in the resistant cultivars ought to have been sufficient for the induction of the disorder.
It is thus obvious that low temperature must induce enzymes that create the scald-causing compounds.
We observed that the concentration of malondialdehyde (MDA) increased only in the areas showing scald symptoms, which in turn indicates that oxidative processes were involved in scald development.
Alternatively, in the resistant cultivars the anti-oxidant capacity may be higher than in the sensitive ones.
In short, the data show that in addition to cultivar type, low temperature and the induction of the C2H4 climacteric play a crucial role in scald development.
Furthermore, if either low O2 or 1-MCP is applied after the initiation of the C2H4 climacteric, their inhibitory effects on scald development decrease.
The treatments that retard the C2H4 climacteric onset also strongly inhibit the rise in
-farnesene and conjugated trienols.In Granny Smith apples, we studied the effect of temperature on scald development, as well as changes in the content of
-farnesene and conjugated trienols.The data show that, at temperatures above 7°C, scald failed to develop but the rise in
-farnesene and conjugated trienols was not affected.It should be noted that in scald-resistant cultivars stored at 1°C there was an increase in both
-farnesene and conjugated trienols, though not as high as in sensitive cultivars.However, if the auto-oxidation of α-farnesene and trienols is the cause of scald disorder, their levels in the resistant cultivars ought to have been sufficient for the induction of the disorder.
It is thus obvious that low temperature must induce enzymes that create the scald-causing compounds.
We observed that the concentration of malondialdehyde (MDA) increased only in the areas showing scald symptoms, which in turn indicates that oxidative processes were involved in scald development.
Alternatively, in the resistant cultivars the anti-oxidant capacity may be higher than in the sensitive ones.
In short, the data show that in addition to cultivar type, low temperature and the induction of the C2H4 climacteric play a crucial role in scald development.
Authors
P. Trivedi, D. Caridhas, T. Solomos
Keywords
α-farnesene, conjugated trienol, hypoxia, 1-MCP, HMGR, FPPS
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