Jc. Beaulieu et al., ACETALDEHYDE IS A CAUSAL AGENT RESPONSIBLE FOR ETHANOL-INDUCED RIPENING INHIBITION IN TOMATO FRUIT, Plant physiology, 113(2), 1997, pp. 431-439
Inhibition of tomato (Lycopersicon escolentum Mill.) fruit ripening by
exogenously applied ethanol was shown to be caused by elevated endoge
nous levels of acetaldehyde (AA). Exposure of excised pericarp discs o
f mature-green tomato fruit to ethanol or AA vapors produced elevated
levels of both compounds in the tissue, but only the levels of AA were
associated with ripening inhibition. Ripening inhibition was dependen
t on both the applied concentration and the duration of exposure. Disc
s treated with inhibitory levels of AA had levels of ethanol that were
elevated but below that associated with inhibition of ripening. The i
n vivo activity of alcohol dehydrogenase was inhibited 40 to 60% by 4-
methylpyrazole (4-MP), a competitive inhibitor of this enzyme. The inh
ibitory effect of ethanol on ripening was reduced by the simultaneous
application of 4-MP. Tissue treated with 4-MP plus AA vapors had highe
r endogenous levels of AA and ripening was inhibited longer than in ti
ssue without 4-h MP. The tissue AA level resulting from ethanol or AA
application appears to be the critical determinant of ripening inhibit
ion.