The natural ethylene production of the unripe mango fruit tissues examined
was very low (~1 nl gg’ h-r) compared to the ethylene producing capacity of the
tissues (approximately 50 nl g-’ h-i) determined by supplying exogenous ACC. It
is under these conditions that the largest effect of acetaldehyde is seen. Increasing
concentrations of acetaldehyde reduced the ethylene producing capacity of the fruit
tissues. Ethanol treatments in the same percentage concentrations failed to inhibit
ACC oxidase activity to the same extent as acetaldehyde, although there was a slight
inhibition. The high ethylene producing capacity of the tissues is largely an effect
of the treatment received in preparing the discs or fruit. This exposes the tissues to
stress (damage and water loss) and thereby elevates ethylene production (Wang et
al., 1990).