A seed contains everything a new plant needs to begin life! Most seeds have three main parts: the embryo, the endosperm, and the seed coat.
The Three Main Parts of a Seed
- Embryo: This is the tiny plant itself, a miniature version of the mature plant. It already contains a root (radicle), a stem (plumule), and one or more leaf-like parts called cotyledons. These cotyledons act as the plant's initial food source until it can photosynthesize.
- Endosperm: This is the seed's food supply, providing nourishment for the embryo as it grows. It's a combination of nutrients like starch, oils, and proteins. The composition varies depending on the plant species.
- Seed Coat: This protective outer layer safeguards the embryo and endosperm from damage and harsh environmental conditions. It helps to prevent desiccation (drying out) and protects against pests and diseases.
Seed Anatomy: A Closer Look
Let's delve a little deeper into the components:
- Cotyledons: These are embryonic leaves; the number of cotyledons (one or two) is a key characteristic used to classify flowering plants (monocots and dicots).
- Hypocotyl: This is the short stem section below the cotyledons. It connects the cotyledons to the radicle.
- Plumule: This is the embryonic shoot, which will develop into the plant's stem and leaves.
- Radicle: This is the embryonic root, the first part of the plant to emerge during germination.
The process of a seed developing into a plant involves imbibition (absorption of water), digestion and translocation of stored food, and finally, germination.
Example: A bean seed, easily dissected, shows these parts clearly. The two large cotyledons store abundant food.
The information above is corroborated by various sources including the New York Botanical Garden (https://www.nybg.org/planttalk/what-is-a-seed/), which states that most seeds have three parts: embryo, endosperm, and seed coat. Other sources, such as the Minnesota DNR (https://www.dnr.state.mn.us/forestry/education/seeds/whatisaseed.html), reinforce the description of the embryo's components.
