The answer is germ of the grain kernel.
A kernel is commonly wrapped in a fibrous outer covering which is intended to be tough as a protection. Inside is the germ which is what the new plant will develop. This is filled with vitamins, fats and phytochemicals. Around the germ is the endosperm. This provide nutrition to the germ. When the seed germinates the germ will draw nutrition from the endosperm which is mainly made of starch.