Synthetic seeds are mostly derived from
1. zygotic embryos
2. fruit of coconut
3. avocado seeds
4. somatic embryos

Detailed Explanation:

Correct Answer: 4. Somatic embryos

Introduction to Synthetic Seeds:

Synthetic seeds are artificially created plant seeds that can be used for the propagation of plants. These seeds are developed from somatic embryos, which are derived from non-reproductive cells. Unlike natural seeds, which develop from fertilized zygotes (the fusion of male and female gametes), synthetic seeds provide a way to propagate plants without requiring sexual reproduction.

Derivation of Synthetic Seeds:

Somatic embryos are the key source of synthetic seeds. These embryos are produced through a process called somatic embryogenesis, where a somatic cell (a non-reproductive cell) is induced to revert to an embryonic state. These embryos resemble zygotic embryos but are produced through tissue culture techniques. Somatic embryos can be encapsulated in a gel or other protective coatings to create synthetic seeds that can be sown just like natural seeds.

How Synthetic Seeds are Created:

• Somatic Embryogenesis: Somatic cells (often from plant tissues like leaves, stems, or roots) are cultured under controlled conditions to induce the formation of embryos.

• Encapsulation: These somatic embryos are then encapsulated in a gel-like substance that helps protect them during transport and planting, mimicking the behavior of natural seeds.

• Germination and Growth: Once planted, synthetic seeds can germinate and grow into mature plants, just like conventional seeds.

Why the Other Options Are Incorrect:

• Option 1: Zygotic embryos: Zygotic embryos are the result of sexual reproduction, formed by the fertilization of an egg cell by a sperm cell. They are the basis of natural seeds, but synthetic seeds are not derived from zygotic embryos.

• Option 2: Fruit of coconut: While coconuts contain seeds, the concept of synthetic seeds involves creating artificial seeds from somatic embryos, not from fruits like coconuts.

• Option 3: Avocado seeds: Avocado seeds are natural seeds that result from sexual reproduction in the avocado plant. Synthetic seeds are not derived from these natural seeds, but rather from somatic embryos.

Advantages of Synthetic Seeds:

1. Clonal Propagation: Synthetic seeds allow for the clonal propagation of plants, ensuring that the offspring are genetically identical to the parent.

2. Preservation of Plant Variety: Synthetic seeds can be used to preserve rare or endangered plant species by creating large numbers of genetically identical plants.

3. Improved Storage and Transport: Unlike traditional seeds, synthetic seeds can be stored and transported more efficiently because they can be engineered for specific purposes.

4. Reduced Time for Propagation: Synthetic seeds can speed up the propagation process compared to growing plants from seeds, especially for crops that do not produce viable seeds.

Conclusion:

Synthetic seeds are primarily derived from somatic embryos, which are created through somatic embryogenesis. This process allows for efficient plant propagation without the need for sexual reproduction, making it a valuable tool in plant biotechnology and agriculture.