Transition of exarch bundles of root to endarch bundles of stem occurs in

Options

A. Epicotyl
B. Hypocotyl
C. Apical bud
D. Coleoptile

Answer

To solve the question regarding the transition of exarch bundles of the root to endarch bundles of the stem, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Vascular Bundles**:
- Vascular bundles in plants consist of xylem and phloem.
- In the context of roots and stems, the arrangement of these bundles can differ.
- **Exarch bundles**: In roots, the protoxylem is located towards the outside, and the metaxylem is towards the inside.
- **Endarch bundles**: In stems, the protoxylem is located towards the inside (near the pith), and the metaxylem is towards the outside.

2. **Identifying the Transition Zone**:
- The transition from the root to the stem occurs in the region where the root (radical) connects to the stem (hypocotyl).
- The hypocotyl serves as the junction between the root and stem, where the vascular arrangement changes from exarch to endarch.

3. **Analyzing the Hypocotyl**:
- In the hypocotyl region, the vascular bundles begin to transition from exarch (typical of roots) to endarch (typical of stems).
- This transition is crucial for the proper functioning of the plant as it grows.

4. **Conclusion**:
- The transition of exarch bundles of the root to endarch bundles of the stem occurs specifically in the hypocotyl region.
- Therefore, the correct answer to the question is that this transition occurs in the hypocotyl.

### Final Answer:
The transition of exarch bundles of the root to endarch bundles of the stem occurs in the **hypocotyl**.

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