Endosperm is a tissue found within the seeds of flowering plants (angiosperms) and is crucial for the development and nutrition of the embryo. It is formed during the process of double fertilization, where one sperm cell fertilizes the egg to form the embryo, and another sperm cell fuses with two polar nuclei to form the triploid endosperm. This tissue serves as a nutrient reservoir, providing essential carbohydrates, proteins, and fats that support the growth of the embryo during seed germination and seedling development. In many grains and seeds, the endosperm constitutes a significant portion of the seed’s volume and is a major source of food for humans and animals.