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Dynamics of acetaldehyde production during anoxia and post-anoxia in red bell pepper studied by photoacoustic techniques

Author:
Zuckerman, H., Harren, F.J.M., Reuss, J., Parker, D.H.
Source:
Plant physiology 1997 v.113 no.3 pp. 925-932
ISSN:
0032-0889
Subject:
Capsicum annuum, oxygen, dose response, hypoxia, acetaldehyde, ethanol, fermentation, catalase, enzyme activity, carbon dioxide, biosynthesis, measurement, tricarboxylic acid cycle, volatile compounds, acoustic properties, stress response
Abstract:
Acetaldehyde (AA), ethanol, and CO2 production in red bell pepper (Capsicum annum L.) fruit has been measured in a continuous flow system as the fruit was switched between 20% O2 and anaerobic conditions. Minimum gas phase concentrations of 0.5 nL L-1, 10 nL L-1, and 1 mL L-1, respectively, can be detected employing a laser-based photoacoustic technique. This technique allows monitoring of low production rates and transient features in real time. At the start of anaerobic treatment respiration decreases by 60% within 0.5 h, whereas AA and ethanol production is delayed by 1 to 3 h. This suggests a direct slow-down of the tricarboxylic acid cycle and a delayed onset of alcoholic fermentation. Reexposure of the fruit to oxygen results in a 2- to 10-fold upsurge in AA production. A short anoxic period leads to a sharp transient peak lasting about 40 min, whereas after numerous and longer anoxic periods, post-anoxic AA production stays high for several hours. High sensitivity of the fruit tissue to oxygen is further evidenced by a sharp decrease in post-anoxic AA production upon an early return to anaerobic conditions. Ethanol oxidation by the "peroxidatic" action of catalase is proposed to account for the immediate postanoxic AA upsurge.
Agid:
664710