Production of Carbonyl Compounds by Tomato Fruit Tissue in the Presence of Aliphatic Alcohols

Abstract

IT is well established that, in the absence of oxygen, many types of plant tissue produce ethanol. Under normal conditions, ethanol, other alcohols and various aldehydes are produced in small amounts by ripening fruits and other plant organs^1–3. The question whether ethanol is metabolized by plant tissues has, on the other hand, been a source of controversy. In recent years Phillips⁴, working with barley seedlings, Wager⁵ with peas and Lowe and James⁶ with mature carrot disks have found no evidence for appreciable utilization of ethanol. However, Cossins and Turner^7–9 showed that ethanol was consumed by the tissue in germinating peas and was converted initially to acetaldehyde and acetone, followed by the production of organic acids and amino-acids. Homogenates of a variety of germinating seeds were shown¹⁰, by redox indicator, to have alcohol dehydrogenase activity when the normal C₂⁻, C₃⁻ and C₄⁻ aliphatic alcohols were added as substrates. Less activity was evident in the presence of the normal C₁⁻ or C₅⁻, secondary C₃⁻ or iso-C₄⁻, and tertiary C₄⁻ or C₅⁻ alcohols. Recently, Cossins and Beevers¹¹ showed that carrot disks, corn and pea shoots, potato disks and castor bean endosperm rapidly metabolized carbon-14-labelled ethanol, while apple tissue consumed it very slowly. Their results suggested that acetyl coenzyme-A was derived from ethanol and converted to lipids, amino-acids, organic acids and sugars by known pathways.