Which of the following types of vascular bundles are found in a monocot root ?

Options

A. Collateral , conjoint and closed
B. Radial vascular bundle with exarch xylem
C. Bicollateral, conjoint and closed
D. Radial vascular bundle with endarch xylem

Answer

To determine the type of vascular bundles found in a monocot root, we can analyze the options provided step by step.

### Step-by-Step Solution:

1. **Understand Vascular Bundles**: Vascular bundles are arrangements of xylem and phloem in plants. They can be classified based on their arrangement and the type of xylem (protoxylem and metaxylem) they contain.

2. **Analyze the Options**:
- **Option 1: Collateral, Conjoined, and Closed**: These types of vascular bundles are typically found in monocot stems, not roots. In monocot stems, the xylem is endarch (protoxylem is located towards the center).
- **Option 2: Radial Vascular Bundle with Exarch Xylem**: This is a characteristic of monocot roots. In this arrangement, the protoxylem is located towards the periphery, which is termed exarch. The arrangement allows for more than six vascular bundles.
- **Option 3: Bicollateral, Conjoined, and Closed**: Similar to option 1, these types are not found in monocot roots but are more common in certain stems.
- **Option 4: Radial Vascular Bundle with Endarch Xylem**: This option is incorrect for monocot roots, as the xylem in monocot roots is exarch, not endarch.

3. **Conclusion**: The correct answer is **Option 2: Radial Vascular Bundle with Exarch Xylem**. This is because the protoxylem in monocot roots faces the periphery, and the vascular bundles are arranged radially.