Yaniv, Z., Dept. of Genetic Rsrc. and Seed Res., ARO, Volcani Center, Bet Dagan, Israel
Shabelsky, E., Dept. of Genetic Rsrc. and Seed Res., ARO, Volcani Center, Bet Dagan, Israel
Schafferman, D., Dept. of Genetic Rsrc. and Seed Res., ARO, Volcani Center, Bet Dagan, Israel
Granot, I., Dept. of Agronomy and Nat. Resources, ARO, Volcani Center, Bet Dagan, Israel
Kipnis, T., Dept. of Agronomy and Nat. Resources, ARO, Volcani Center, Bet Dagan, Israel

Seeds of Sinapis alba L. and Crambe abyssinica L. contain oil, rich in erucic acid (50-60%), which is valuable for industrial purposes. During germination and early growth at 20°C changes in lipid content and fatty acid composition were followed for 15 days. Reduction in the oil content started only 8 days after the onset of germination and was more rapid in C. abyssinica. 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, respectively. No change in dry weight was observed during this period. In cotyledons of 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, the decline in erucic acid was accompanied by significant increases in linolenic acid (32% in S. alba and 27% in C. abyssinica) which was also stimulated by light (to 45 and 32%, respectively). No synthesis of linolenic acid was detected in the roots of either species. However, a novel synthesis of saturated palmitic and stearic acids was observed in these species, with a 10-fold increase in their contents. The present results provide an example of the selective utilization of the fatty acids in the reserve oil of seeds during germination and the subsequent growth of seedlings.