Glycerolipid Evolution During Safflower Seed Formation and Ripening

Lipid accumulation during formation and ripening of safflower seeds by plants cultivated in the north‐west of Tunisia was evaluated. The results obtained showed an increase in oil content and total lipids. At the level of fatty acids, seed replenishment resulted mainly in an increase in the rate and the amounts of linoleic acid (C18:2), the major fatty acid identified in seeds (75% of total fatty acids). The ripening process of safflower seeds was also characterized by an increase in the content of triacylglycerols (TAG) and a decrease in the diacylglycerols (DAG), phosphatidylcholine (PC) and phosphatidic acid (PA) contents. To explain these results, the hypothesis of TAG biosynthesis from PC and PA via DAG was advanced and discussed. Finally, ripening of safflower seeds was characterized by a decrease in the amounts of main galactolipids, indicating a decrease of the photosynthetic activity in storage tissues.