Bark includes -

Options

A. Cork + Phellogen + Phelloderm + Secondary phloem
B. Periderm only
C. Secondary xylem + Secondary phloem
D. Secondary xylem + Cambial ring + Secondary phloem

Answer

**Step-by-Step Text Solution:**

1. **Understanding Bark Composition:**
- Bark is primarily composed of several layers of tissues found outside the vascular cambium in a plant stem.

2. **Identifying the Components of Bark:**
- The main components of bark include:
- **Cork (Phellem):** This is the outermost layer that protects the plant.
- **Phellogen (Cork Cambium):** This is a meristematic tissue that produces cork cells.
- **Phelloderm:** This is the inner layer of the periderm, which is formed by the cork cambium.
- **Secondary Phloem:** This is the layer of phloem that is produced during secondary growth.

3. **Clarifying the Role of Vascular Cambium:**
- The vascular cambium is a layer of cells that contributes to the growth of secondary xylem (wood) and secondary phloem (part of the bark). It is located between the xylem and phloem.

4. **Understanding Periderm:**
- The periderm consists of the cork, phellogen, and phelloderm. It replaces the epidermis in plants undergoing secondary growth.

5. **Conclusion:**
- Therefore, the correct components included in bark are cork, phellogen, phelloderm, and secondary phloem.

**Final Answer:**
Bark includes cork, phellogen, phelloderm, and secondary phloem.

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