Oil is the prefer energy storing molecule in seeds of several plants, while excess energy in other parts of the plant is stored as starch. This is related to
(1) the requirement of concentrated form of energy in seeds in order to make them light in weight and facilitate their dispersal.
(2) dependence of the seeds totally on the stored fat for germination
(3) protective role of the oil against insect pests
(4) the antioxidant role of the soils