Total fatty acid and polar lipid content in developing flower of Nicotiana tabacum. Plant and Cell Physiology 24

Flower organs of Nicotiana tabacum had lower ratios of linolenic acid than the leaf at all stages of development. The petal, ovary and anther (before anthesis) had linoleic acid as the major fatty acid, and the pistil had high amounts of oleic acid. As for polar lipids, flower organs generally had lower proportions of chloroplast lipids than the leaf, which resulted in a high proportion of phospholipids such as phosphatidylcholine, phos-phatidylinositol and phosphatidylethanolamine. The fatty acid compositions of these phospholipids did not change significantly between the early bud stage and the fully opened flower stage, whereas those of monogalactosyldiglyceride and digalactosyldigly-ceride changed significantly. The oleic acid-rich substances in the pistil were not detected in the polar lipid regions. Hexadecenoic and hexadecatrienoic acids, which are characteristic of the phosphatidylglycerol and monogalactosyldiglyceride, respective-ly, in the leaf, were detected in small amounts in the petal, but not in other flower organs. Key words: Fatty acid composition — Flower organs — Nicotiana tabacum — Polar lipids. Polar lipids in nongreen tissues such as inner leaves of cabbage (Nicholas 1963), root