What does the endosperm do in a grain?

In a grain, the endosperm primarily serves as a source of stored nutrients that fuel the early growth of the seedling. It contains carbohydrates, mainly in the form of starch, which are broken down into simpler sugars during germination. These sugars provide energy for the developing embryo. Additionally, the endosperm contains proteins and fats that contribute to the overall nutrient profile of the seed. Its role is crucial in supporting the seedling’s initial growth until it can establish itself and begin photosynthesis.