Oil and fatty acid changes in Sinapis and Crambe seeds during germination and early development

Seeds of Sinapis alba L. and Crambe abyssinica L. contain oil, rich in eruc ic acid (50-60%), which is valuable for industrial purposes. During germina tion and early growth at 20 degrees C changes in lipid content and fatty ac id composition were followed for 15 days. Reduction in the oil content star ted only 8 days after the onset of germination and was more rapid in C. aby ssinica. Oil reduction was accelerated by light and the content reached low levels of 6.7 and 13.7% in seeds of C. abyssinica and S. alba, respectivel y. No change in dry weight was observed during this period. In cotyledons o f S. alba and C. abyssinica respectively, levels of 12 and 25% erucic acid were found after 15 days of development in darkness. Lower levels (4 and 18 %) were found in cotyledons developed in the light. No more than 5% erucic acid was detected in the 15-day-old roots of both species. In cotyledons, t he decline in erucic acid was accompanied by significant increases in linol enic acid (32% in S. alba and 27% in C. abyssinica) which was also stimulat ed by light (to 45 and 32%, respectively). No synthesis of linolenic acid w as detected in the roots of either species. However, a novel synthesis of s aturated palmitic and stearic acids was observed in these species. with a 1 0-fold increase in their contents. The present results provide an example o f the selective utilization of the fatty acids in the reserve oil of seeds during germination and the subsequent growth of seedlings. (C) 1998 Elsevie r Science B.V. All rights reserved.