Seed dormancy can be broken by

Options

A. ABA and `GA_(3)`
B. `GA_(3)` and ethylene
C. IAA and ABA
D. ABA and IPA.

Answer

**Step-by-Step Solution:**

1. **Understanding Seed Dormancy**: Seed dormancy is a physiological state in which seeds are inactive and do not germinate, even under favorable conditions. This dormancy can be due to various factors, including the presence of inhibitors.

2. **Identifying Hormones Involved**: To break seed dormancy, certain plant hormones are known to play a crucial role. The key hormones that can help in breaking seed dormancy are gibberellins (specifically gibberellic acid 3 or GA3) and ethylene.

3. **Role of Gibberellins**: Gibberellic acid (GA3) is known to promote seed germination by stimulating the mobilization of stored food reserves within the seed. It helps in breaking dormancy by overcoming the inhibitors present.

4. **Role of Ethylene**: Ethylene is another hormone that can assist in breaking seed dormancy. It works alongside gibberellins to promote germination and growth processes in seeds.

5. **Exclusion of Other Hormones**: Other hormones mentioned, such as abscisic acid (ABA) and indole acetic acid (IAA), do not play a role in breaking seed dormancy. In fact, ABA is known to promote dormancy, while IAA primarily influences growth and elongation.

6. **Conclusion**: Based on the roles of these hormones, the correct answer to the question of what can break seed dormancy is **gibberellic acid 3 (GA3) and ethylene**.

**Final Answer**: Seed dormancy can be broken by gibberellic acid 3 (GA3) and ethylene.

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