What are the parts of a seed, and how does each part contribute to the development of a seedling?

The seed coat is the outer protective covering of a seed. It protects the inner parts of the seed from physical damage, insects, and diseases. The seed coat also prevents water loss and prevents the seed from germinating prematurely. When the seed absorbs water, the seed coat softens, allowing the embryo to emerge and grow into a seedling.

The endosperm is the food storage tissue within the seed. It is rich in nutrients such as carbohydrates, proteins, and lipids, which provide energy and nourishment for the embryo during germination. Once the seed germinates and begins to grow, the seedling consumes the endosperm's stored nutrients to support its initial growth until the seedling produces its own food through photosynthesis.

The embryo is the young plant in the early stages of development within the seed. It consists of the root (radicle), shoot (plumule) and cotyledons (seed leaves). During germination, the radicle emerges first and forms the primary root, anchoring the seedling and absorbing water and minerals from the soil. The plumule then emerges and forms the shoot, which will grow into the future stem, branches, and leaves of the plant. The cotyledons provide additional nutrients to the seedling and may either remain underground or lift above the soil surface, depending on the plant type. By understanding the roles and functions of the seed coat, endosperm, and embryo, we can appreciate the process of seed germination and the development of a seedling from a seed.