DEVELOPMENT OF OIL IN THE SEED OF HELIANTHUS ANNUUS L.

Abstract

Sunflower seed (Helianthus annuus L.) was collected from growing plants at weekly intervals. Analyses of the seed, the oil, and the fatty acids were made, the latter by gas chromatography. Oil formation began about 10 days after flowering and continued at a steady rate for 7 weeks. There was no evidence that any intermediate substance accumulated in the seed for subsequent conversion to oil.The weight of individual fatty acids per 100 seeds was determined at each stage of development. Except for one sample, the amount of each acid increased to maturity. Oleic acid accumulated most rapidly at first but at the mid-point of oil development it was overtaken by linoleic acid, which became the major component. The possibility that some oleic acid was converted to linoleic acid is discussed. The absence of any marked change in amounts of long-chain saturated acids suggests that they were not involved in the synthesis of the unsaturated fatty acids.