Fatty acid and glycerolipid synthesis in abscised daffodil flowers after acetate feeding.

The coronae of Narcissus pseudonarcissus flowers incorporated [1-(14)C]acetate almost exclusively into the fatty acid moieties of glycerolipids. After a 4 h incubation, the newly synthesized acids were: stearate plus palmitate (50%); oleate (17%); linoleate (32%); and linolenate (0.5%). Phosphatidylcholine and diacylglycerol were the principal labelled lipids. In pulse experiments these acids were further desaturated, with time, to an appreciable extent and, concurrently, transferred essentially from phosphatidylcholine to diacylglycerol, diacylgalactosylglycerol, and diacylgalabiosylglycerol. The labelling of diacylgalactosylglycerol and diacylgalabiosylglycerol paralleled the appearance of linolenate. The distribution of labelled acids in phosphatidylcholine, diacylgalactosylglycerol, and diacylgalabiosylglycerol was very different. The results were compared with those obtained in vitro with isolated coronae chromoplasts and discussed in relation to current schemes of fatty acid and glycerolipid synthesis in plant cells.