The nutrient involved in oil-biosynthesis is

The nutrient involved in oil-biosynthesis is Sulphur.
Oil crops respond to the application of sulphur, moreover, the sulphur requirement is the highest in oil crops in comparison with other crops, which is related to the role of this nutrient in oil biosynthesis.
Sulphur is a component of plant amino acids, proteins, vitamins and enzyme structures. Sulphur is essential for many growth functions in plants including nitrogen metabolism, enzyme activity, and protein and oil synthesis.