Production, transport, and metabolism of ethanol in eastern cottonwood

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1991

OSTI ID:7175012

MacDonald, R C

In plant tissues, the production of acetaldehyde and ethanol are usually thought to occur as a mechanism to allow tolerance of hypoxic conditions. Acetaldehyde and ethanol were found to be common in vascular cambium and the transpiration stream of trees. Ethanol concentrations in the vascular cambium of Populus deltoides were not changed by placing logs from nonflooded trees in a pure oxygen environment for as long as 96 h, but increased by almost 3 orders of magnitude when exposed to low external pO[sub 2]s. Ethanol is present in the xylem sap of flooded and nonflooded trees. Because of the constitutive presence of alcohol dehydrogenase in the mature leaves of woody plants, it was hypothesized that the leaves and shoots of trees had the ability to metabolize ethanol supplied by the transpiration stream. 1-[[sup 14]C]ethanol was supplied to excised leaves and shoots of Populus deltoides Bartr. in short- and long-term experiments. Greater than 99% of the radiolabel was incorporated into plant tissue in short-term experiments, with more than 95% of the label remaining in plant tissue after 24 h. Very little label reached the leaf mesophyll cells of excised shoots, as revealed by autoradiography. Radiolabel appeared primarily in the water- and chloroform-soluble fractions in short-term experiments, while in long-term experiments, label was also incorporated into protein. When labelled ethanol was supplied to excised petioles in a 5 min pulse, 41% of the label was incorporated into organic acids. Some label was also incorporated into amino acids, protein, and the chloroform-soluble fraction, with very little appearing in neutral sugars, starch, or the insoluble pellet. Labelled organic acids were separated by HPLC, and were comprised of acetate, isocitrate, [alpha]-ketoglutarate, and succinate. There was no apparent incorporation of label into phosphorylated compounds.

• Research Organization: Kentucky Univ., Lexington, KY (United States)
• OSTI ID: 7175012
• Country of Publication: United States
• Language: English

Related Subjects

550501 -- Metabolism-- Tracer Techniques
560300* -- Chemicals Metabolism & Toxicology
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ACETALDEHYDE
ALCOHOL DEHYDROGENASE
ALCOHOLS
ALDEHYDES
AUTORADIOGRAPHY
BIOSYNTHESIS
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
ENZYME ACTIVITY
ENZYMES
ETHANOL
HEMIACETAL DEHYDROGENASES
HYDROXY COMPOUNDS
LABELLED COMPOUNDS
MEMBRANE TRANSPORT
METABOLISM
ORGANIC COMPOUNDS
OXIDOREDUCTASES
PLANTS
PROTEINS
SYNTHESIS
TREES