Choose correct option w.r.t. origin of cork cambium in dicot stem and root

Options

A. Completely primary in both
B. Completely secondary in both
C. Partly primary and partly secondary in both
D. Primary in stem and secondary in root

Answer

To answer the question regarding the origin of cork cambium in dicot stem and root, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Cork Cambium**:
- Cork cambium is a type of secondary meristem. It plays a crucial role in the formation of the protective outer layer of the plant, known as the periderm.

2. **Distinction Between Primary and Secondary Meristem**:
- Primary meristems are responsible for the elongation of the plant, contributing to the increase in height.
- Secondary meristems, including cork cambium, are responsible for the thickening or increase in girth of the plant.

3. **Origin of Cork Cambium**:
- Cork cambium arises during the secondary growth phase of the plant. It develops from the pericycle in roots and from the outer layers of the cortex in stems.

4. **Cork Cambium in Dicot Stem and Root**:
- In both dicot stems and roots, cork cambium is derived from secondary meristematic tissues. This means that it is not present from the beginning (as a primary meristem) but develops as the plant matures.

5. **Conclusion**:
- Since cork cambium is a secondary meristem in both the stem and root, the correct option regarding its origin is that it is "completely secondary in both."

### Final Answer:
The correct option is: **completely secondary in both stem and root.**

---