FORMATION OF OIL IN THE SEED OF RICINUS COMMUNIS L.

Abstract

Castor seeds were collected at 3- and 6-day intervals after blossoming until maturity. The seeds were analyzed for protein and oil content and the fatty acid composition of the oil was determined by gas–liquid chromatography. Oil formation began 21 days after blossoming and two-thirds of the oil was synthesized in the next 20 days; the remaining one-third was formed in the last 20-day period. Protein synthesis occurred over a longer period of time but was accelerated during the middle 20-day period.Ricinoleic acid, the characteristic component of castor oil, was not present in the very young seed, but appeared when the seed was 12 days old and represented 90% of the fatty acids when the seed was 36 days old. After this time the fatty acid composition of the oil remained constant and characteristic. In the intervening 24-day period, the amount of ricinoleic acid was lower than normal. The amount of each fatty acid component, expressed on a per seed basis, increased over the entire period of development and there was no evidence of substantial conversion of oleic or linoleic acid to ricinoleic acid.