Question

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

Short answer

The three main parts of a seed are the seed coat, endosperm, and embryo. The seed coat offers protection to the inner parts from damage, insects, diseases, and water loss, while also controlling germination. The endosperm stores nutrients, providing energy and nourishment for the embryo during germination. The embryo, consisting of a root, shoot, and cotyledons, develops into the mature plant, with the root absorbing water and minerals, and the shoot and cotyledons supporting growth and providing nutrients.

Step-by-step solution

Part 1: Seed Coat

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.

Part 2: Endosperm

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.

Part 3: Embryo

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.