In dicot root, during secondary growth, vascular cambium is formed from

Options

A. only pericycle
B. pericycle present in contact with protoxylem and conjuctive tissue present below the phloem
C. complete ring of pericycle and conjunctive tissue present below the xylem
D. complete ring of pricycle and total conjunctive tissue

Answer

### Step-by-Step Solution:

1. **Understanding Secondary Growth in Dicot Roots**:
- Secondary growth refers to the increase in thickness of the plant, which occurs due to the activity of the vascular cambium and cork cambium.
- In dicot roots, secondary growth is similar to that in dicot stems.

2. **Identifying the Vascular Cambium**:
- Vascular cambium is a type of meristematic tissue that is responsible for the production of secondary xylem (wood) and secondary phloem (inner bark).
- It is located between the xylem and phloem.

3. **Source of Vascular Cambium in Dicot Roots**:
- In dicot roots, the vascular cambium is formed from the pericycle and the conjunctive tissue.
- The pericycle is a layer of cells that lies just inside the endodermis and is involved in the formation of lateral roots.

4. **Specific Location of Formation**:
- The vascular cambium in dicot roots arises specifically from the pericycle that is in contact with the protoxylem and the conjunctive tissue located below the phloem.
- This means that the cambium is formed from a combination of the pericycle and the conjunctive tissue.

5. **Conclusion**:
- Therefore, the correct answer to the question is that in dicot roots during secondary growth, the vascular cambium is formed from the pericycle present in contact with protoxylem and conjunctive tissue present below the phloem.

### Final Answer:
The vascular cambium in dicot roots during secondary growth is formed from the pericycle present in contact with protoxylem and conjunctive tissue present below the phloem.

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