Amphicribral vascular bundles are

Options

A. Endarch
B. Exarch
C. Mesarch
D. All of these

Answer

**Step-by-Step Solution:**

1. **Understanding Vascular Bundles**: Vascular bundles are arrangements of xylem and phloem in plants. They are crucial for the transport of water, nutrients, and food.

2. **Classification of Vascular Bundles**: Vascular bundles can be classified based on the spatial arrangement of xylem and phloem. The two main types are:
- **Amphicribral**: Xylem is in the center, surrounded by phloem.
- **Amphivasal**: Phloem is in the center, surrounded by xylem.

3. **Defining Amphicribral Vascular Bundles**: Amphicribral vascular bundles specifically have the xylem located at the center, with phloem encircling it. This arrangement is also referred to as hydrocentric.

4. **Development of Xylem in Amphicribral Bundles**: In amphicribral vascular bundles, the protoxylem (the first-formed xylem) develops at the center of the bundle. It expands both centrifugally (outward) and centripetally (inward).

5. **Mesarch Xylem**: The type of xylem development seen in amphicribral bundles is referred to as mesarch xylem, which indicates that the xylem develops from the center and spreads outwards as well as inwards.

6. **Final Conclusion**: Therefore, amphicribral vascular bundles are characterized by mesarch xylem, where the xylem is centrally located and surrounded by phloem.

**Final Answer**: Amphicribral vascular bundles are mesarch.

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