Identify the mismatch with reference to antagonistic effects shown by a pair of hormones

Options

A. promotion of flowering in pineapple - Auxins and Ethylene
B. Seed dormancy - ABA and `GA_5`
C. Apical dominance - Auxins and Cytokinins
D. Senescence in leaves - Cytokinins and Ethylene

Answer

To identify the mismatch with reference to the antagonistic effects shown by a pair of hormones, we will analyze the provided options step by step.

### Step 1: Understand the Concept of Antagonistic Hormones
Antagonistic hormones are pairs of hormones that have opposite effects on a particular physiological process. For example, one hormone may promote a process while the other inhibits it.

### Step 2: Analyze Each Option
1. **Option 1: Promotion of flowering in pineapple - Auxin and Ethylene**
- **Analysis**: Ethylene is known to promote flowering in pineapples, while auxin (Indole-3 Acetic Acid) also plays a role in promoting flowering. Therefore, this pair does not show antagonistic effects; instead, they work together. This is a mismatch.

2. **Option 2: Seed Dormancy - Abscisic Acid and Gibberellic Acid**
- **Analysis**: Abscisic Acid (ABA) is known to maintain seed dormancy, while Gibberellic Acid (GA) promotes seed germination. This pair shows antagonistic effects, as one hormone inhibits the process (dormancy) while the other promotes it (germination).

3. **Option 3: Apical Dominance - Auxins and Cytokinins**
- **Analysis**: Auxins promote apical dominance, while cytokinins can inhibit it. This pair also shows antagonistic effects.

4. **Option 4: Senescence in Leaves - Cytokinins and Ethylene**
- **Analysis**: Cytokinins are known to inhibit leaf senescence, while ethylene promotes it. This pair also shows antagonistic effects.

### Step 3: Identify the Mismatch
From the analysis, we can conclude that:
- **Option 1** is the mismatch because both auxin and ethylene promote flowering in pineapples, rather than having antagonistic effects.

### Final Answer
The mismatch with reference to antagonistic effects shown by a pair of hormones is:
**Option 1: Promotion of flowering in pineapple - Auxin and Ethylene.**

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