Which hormone is not translocated? 

Options

A. Auxin
B. Ethylene
C. ABA
D. Cytokinin.

Answer

To determine which hormone is not translocated, we need to analyze the characteristics of various plant hormones and their movement within the plant. Here’s a step-by-step solution:

### Step 1: Understand Hormone Translocation
- Plant hormones are typically synthesized in one part of the plant and then transported (translocated) to other parts where they exert their effects.

### Step 2: Analyze Auxins
- Auxins are synthesized in the stem tips and are translocated through parenchyma cells to different sites of action. Therefore, auxins are translocated.

### Step 3: Examine Ethylene
- Ethylene is a gaseous hormone, often referred to as the fruit ripening hormone. It diffuses through intracellular spaces rather than being transported through vascular tissues. This means that ethylene does not require translocation via specific tissues.

### Step 4: Look at Abscisic Acid (ABA)
- Abscisic acid (ABA) is a stress hormone that is synthesized in various parts of the plant and is translocated through vascular tissues. Hence, ABA is translocated.

### Step 5: Consider Cytokinins
- Cytokinins are synthesized in the roots and are transported via the xylem to other parts of the plant. Therefore, cytokinins are also translocated.

### Conclusion
- Based on the analysis, the only hormone that is not translocated through specific tissues is ethylene. Therefore, the answer to the question is **ethylene**.

### Final Answer
- The hormone that is not translocated is **ethylene**.

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