What are the functions of endosperm in plant seeds?

The endosperm is usually located around the embryo and is white. Endosperm cells are rich in nutrients, such as starch, protein or fat. Endosperm is the vegetative tissue in seeds, which generally develops earlier than embryo and provides nutrition for embryo development. The seeds of many plants are completely absorbed by embryos during the process of embryo formation and development, and nutrients are stored in cotyledons. After the seed matures, it has no endosperm or only a thin layer remains, becoming an endosperm-free seed.

There are often cotyledons in endosperm-free seeds, such as seeds of Leguminosae, Cucurbitaceae, Rosaceae and Compositae, such as soybean, apricot, pumpkin, sunflower and Alisma orientale. If the seed still has developed endosperm when it matures, it is called endosperm seed, such as the seeds of Gramineae, Solanaceae, Umbelliferae and other plants.