Seed

A seed is the reproductive unit of a flowering plant, containing the embryo and the nutrients it needs to germinate and grow into a new plant. Seeds are essential for the continuation of plant species and are the result of the process of sexual reproduction in plants.

Seed Structure

A typical seed consists of three main parts:

1. Seed Coat: The outer covering of the seed that protects the embryo from mechanical injury, pathogens, and drying out.
2. Embryo: The immature plant inside the seed that will develop into a new plant under the right conditions.
3. Endosperm or Cotyledons: The nutrient-rich tissue that provides food for the embryo during germination until it can produce its own food through photosynthesis.

Seed Germination

Germination is the process by which a seed begins to grow into a new plant. It involves the following steps:

1. Water Absorption: The seed absorbs water, causing it to swell and activate metabolic processes.
2. Seed Coat Splitting: The seed coat ruptures, allowing the embryo to grow and emerge from the seed.
3. Root and Shoot Formation: The radicle (embryonic root) emerges first, followed by the hypocotyl (embryonic shoot), which develops into the stem and leaves.
4. Photosynthesis: Once the seedling has emerged from the soil, it begins to photosynthesize and produce its own food.

Seed Dispersal

Seeds are dispersed from the parent plant to new locations in various ways, such as:

• Wind: Seeds with specialized structures like wings or hairs are carried by the wind to new areas.
• Water: Some seeds float and are transported by water currents to new locations.
• Animals: Seeds may be carried by animals that eat the fruits containing the seeds or by attaching to fur or feathers.
• Self-Dispersal: Some plants have mechanisms to disperse their own seeds, such as explosive seed pods or twisting seed dispersal.

Study Guide

Use the following questions to guide your study of seeds:

1. What are the main parts of a seed and their functions?
2. Describe the process of seed germination and the conditions needed for successful germination.
3. Explain the different methods of seed dispersal and provide examples of plants that use each method.
4. How do seeds contribute to the continuation of plant species?
5. Discuss the importance of seeds in agriculture and food production.

By understanding the structure, germination, and dispersal of seeds, you can appreciate the vital role they play in the life cycle of plants and ecosystems.