In pteridophytes and gymnosperms, xylem consists of all except -

Options

A. Vessel
B. Tracheid
C. Fibre
D. Parenchyma

Answer

To solve the question "In pteridophytes and gymnosperms, xylem consists of all except -", we need to analyze the components of xylem in these two groups of plants.

### Step-by-Step Solution:

1. **Understand the Components of Xylem**:
- Xylem is a type of vascular tissue responsible for the transport of water and nutrients in plants. It typically consists of several types of cells, including vessels, tracheids, fibers, and parenchyma.

2. **Identify the Groups of Plants**:
- Pteridophytes (ferns and their relatives) and gymnosperms (like conifers) are two groups of vascular plants that have specific characteristics in their xylem structure.

3. **Examine the Options Given**:
- **Option 1: Vessels** - These are specialized structures for water transport, typically found in angiosperms (flowering plants).
- **Option 2: Tracheids** - These are long, narrow cells that help in water conduction and are present in both pteridophytes and gymnosperms.
- **Option 3: Fibers** - These provide structural support and are also present in both pteridophytes and gymnosperms.
- **Option 4: Parenchyma** - These are living cells that can store food and are found in the xylem of both pteridophytes and gymnosperms.

4. **Determine Which Component is Absent**:
- In pteridophytes and gymnosperms, vessels are not present. Instead, they primarily rely on tracheids for water conduction. Therefore, vessels are the only component listed that is not found in the xylem of these groups.

5. **Conclude the Answer**:
- The answer to the question is **Option 1: Vessels**.

### Final Answer:
In pteridophytes and gymnosperms, xylem consists of all except **vessels**.