This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Web of Science (29) Citing Articles via Google Scholar Google Scholar Articles by Whitman, C. E. Articles by Travis, R. L. Search for Related Content PubMed PubMed Citation Articles by Whitman, C. E. Articles by Travis, R. L. Agricola Articles by Whitman, C. E. Articles by Travis, R. L.

Articles

Phospholipid Composition of a Plasma Membrane-Enriched Fraction from Developing Soybean Roots

Department of Agronomy and Range Science, University of California, Davis, California 95616

Phospholipid polar head group and fatty acid composition were determined for plasma membrane enriched fractions from developing soybean root (Glycine max [L.] Merr. cult. Wells II). Plasma membrane vesicles were isolated from meristematic and mature sections of four-day-old dark grown soybean roots at pH 7.8 and in the presence of 5 millimolar ethylenediaminetetraacetate, 5 millimolar ethyleneglycol-bis (-aminoethyl ether)N,N tetraacetic acid, and 10 millimolar NaF. Lipid extracts analyzed for phospholipid composition revealed two major phospholipid components: phosphatidylcholine and phosphatidylethanolmine. Minor phospholipid components identified were phosphatidylinositol, phosphatidylserine, phosphatidylglycerol, and diphosphatidylglycerol. Lipid degradation by endogenous phospholipase D during membrane isolation at pH 6.5 and in the absence of chelating agents and NaF resulted in the recovery of large amounts of phosphatidic acid. Phosphatidylcholine was the principal substrate for phospholipase D.

Fatty acid composition was determined for plasma membrane phosphatidylcholine and phosphatidylethanolamine from meristematic and mature root tissue. The fatty acids identified were 16:0, 18:0, 18:1, 18:2, and 18:3. Fatty acid composition varied with both phospholipid class and the developmental stage of the root. Results suggest that differences in the composition of the major phospholipids of plasma membrane from meristemaic and mature root sections occur in the fatty acids and not in the polar head groups. These differences and those found in the composition of the polar head groups of the minor phospholipid components, e.g. phosphatidylglycerol, may be significant for structure-function relationships within the membrane.