Formation of vascular rays occurs in which order?

Options

A. Centripetal
B. Centrifugal
C. Basipetal order
D. 1 and 2 both

Answer

### Step-by-Step Solution:

1. **Understanding Vascular Cambium**:
- Vascular cambium is a type of lateral meristem that is responsible for the secondary growth in plants. It forms secondary xylem (wood) and secondary phloem (bark).

2. **Formation of Vascular Rays**:
- Vascular rays are formed from the ray initials of the vascular cambium. These initials divide tangentially, producing cells that differentiate into parenchymatous cells.

3. **Direction of Growth**:
- The growth of vascular rays can occur in two directions:
- **Centripetal**: This refers to the growth that moves towards the center of the plant, meaning the rays extend from the pith towards the cortex through the secondary xylem.
- **Centrifugal**: This refers to the growth that moves outward, away from the center, extending towards the outer layers of the plant.

4. **Types of Growth Patterns**:
- The growth patterns can be categorized as:
- **Centripetal Order**: Growth towards the center.
- **Centrifugal Order**: Growth away from the center.
- **Acropetal Order**: Growth from base to apex, typically seen in leaves and flowers.

5. **Conclusion**:
- In the context of vascular rays formation, both centripetal and centrifugal growth patterns are involved. Therefore, the formation of vascular rays occurs in both centripetal and centrifugal orders.

### Final Answer:
The formation of vascular rays occurs in both centripetal and centrifugal orders.

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