Accumulation of storage protein and 7S globulins during zygotic and somatic embryo development in Elaeis guineensis

The 7S globulins are the predominant storage proteins in oil palm (Elaeis guineensis Jacq.) zygotic embryos. The accumulation of these proteins was studied in embryos during seed development and in single somatic embryos cultured in vitro. Antibodies raised against these proteins were used for their detection by western blot and quantification with ELISA. In zygotic embryos, the 7S globulins were deposited mainly between the 14th and the 17th post-anthesis week, corresponding to the end of embryo growth. This represented 10 % of the dry weight and 50 % of soluble proteins. The amount of soluble proteins and 7S globulins in somatic embryos increased rapidly during the early stage of development, but were almost 80 times lower than in zygotic embryos. In somatic embryos, 7S globulins represented 0.3 % of dry weight and 4 % of soluble proteins. After 22 days development, the protein content declined slowly, suggesting a lack of embryo maturation and an early germination.