Ethylene, Ethane, Acetaldehyde, and Ethanol Production By Plants under Stress

Abstract

Red pine (Pinus resinosa Ait.) and paper birch (Betula papyrifera marsh.) seedlings exposed to SO2 produced acetaldehyde and ethanol, and exhibited increased production of ethylene and ethane. Gas chromatographic measurement of head space gas from incubation tubes containing leaves or seedlings was a simple method of simultaneously measuring all 4 compounds. Increased ethylene production had 2 phases, a moderate increase from the beginning of the stress period and a large increase just prior to appearance of leaf lesions. Ethane production in SO2-stressed plants did not increase until lesions appeared. Acetaldehyde and ethanol production began within 6 h at 0.3 .mu.l/l SO2 and 24 h at 0.1 .mu.l/l SO2 and continued throughout a 6-day fumigation. Production of acetaldehyde and ethanol continued when plants were removed to clean air for up to 2 days. A higher concentration of SO2 (0.4 .mu.l/l) induced acetaldehyde and ethanol production within 2 h of the start of fumigation of birch and pine seedlings. A number of other stresses, including water deficit, freezing and O3 exposure induced production of acetaldehyde and ethanol. Production of these compounds was not due to hypoxia, as the O2 partial pressure [PO2] in the incubation vessels did not decline. Increasing the PO2 to 300 mm Hg did not affect production of these compounds. Production of ethylene, acetaldehyde and ethanol declined when > 80% of the leaf area became necrotic, while ethane production was linearly related to the percentage of necrosis. A number of woody and herbaceous plant species [Zea mays, Cucurbita maxima, Pisum sativum, Brassica oleracea, Tagetes erecta, Haemanthus katherinae, Platamus occidentalis, Ulmus americana, Eucalyptus camaldulensis, Quercus macrocarpa and Pinus halepensis] produced acetaldehyde and ethanol in response to freezing stress, while others did not. Measurement of these 4 compounds simultaneously in the gas phase may be a valuable method for monitoring plant stress, particularly air pollution stress.