PLANT PHYSIOLOGY , Vol 107, Issue 4 1433-1438, Copyright © 1995 by American Society of Plant Biologists
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BIOCHEMISTRY AND ENZYMOLOGY |
Oleic Acid and Its Positional Isomer, cis-Vaccinic Acid, in the Appendix of Sauromatum guttatum during Anthesis
H. Skubatz, E. R. Svee, B. S. Moore, W. N. Howald, W. Tang and BJD. Meeuse
Departments of Botany (H.S., B.J.D.M.), Chemistry (B.S.M.), and Medicinal Chemistry (W.N.H.), University of Washington, Seattle, Washington 98195
The fatty acid profiles of various organs of the thermogenic inflorescence
of Sauromatum guttatum and of the sporophylls of thermogenic male cones of
two cycad species (Encephalartos ferox and Dioon edule var edule and var
angustifolium) were determined by gas chromatography. During anthesis,
palmitate (16:0), oleate [18:1 (9)], cis-vaccinate [18:1 (11)], and
linoleate [18:2 (9, 12)] were the most abundant fatty acids in the
Sauromatum appendix. cis-Vaccinic acid, a positional isomer of oleic acid,
was identified by comparing its retention time on a gas chromatography
column and its mass spectrum to an authentic compound. The percentage of
oleic acid from total fatty acids dropped from about 9 in the morning 3 d
before heat production to 6 in the morning 2 d before heat production. At
this time, the percentage of cis-vaccinic acid increased from 3 to 11%, and
then remained at this level until the inflorescence dried and died.
Palmitoleic acid [16:1 (9)], the common precursor of cis-vaccinic acid, is
a minor component of total fatty acids. In six other organs of the
Sauromatum inflorescence including thermogenic organs, such as male flowers
and lower spadix, palmitate, oleate, and linoleate were prevalent but
cis-vaccinate was not. The thermogenic male cones of the two cycad species
were rich in palmitic, oleic, and linolenic acids. The level of
cis-vaccinic acid in these organs was less than 0.5%.
