In the period of plant growth, in elongation phase cells are characterised by
I. Increased vacuolation II. Increased cell enlargment III. Increase in thickness of protoplasm IV. New cell wall deposition

Options

A. I and II only are correct
B. I, II and III only are correct
C. II and III only are correct
D. I, II and IV only are correct

Answer

To solve the question regarding the characteristics of cells during the elongation phase of plant growth, we will analyze each option provided.

### Step-by-Step Solution:

1. **Understanding the Elongation Phase**:
- The elongation phase is a critical part of plant growth where cells increase in size. This phase is characterized by specific cellular changes.

2. **Analyzing Option I: Increased Vacuolation**:
- During the elongation phase, cells experience increased vacuolation. Vacuoles expand, which helps in cell enlargement.
- **Conclusion**: This option is **correct**.

3. **Analyzing Option II: Increased Cell Enlargement**:
- Cell enlargement is a hallmark of the elongation phase. As vacuoles expand, the cells increase in size, contributing to the overall growth of the plant.
- **Conclusion**: This option is **correct**.

4. **Analyzing Option III: Increase in Thickness of Protoplasm**:
- In the elongation phase, the focus is on cell expansion rather than thickening of the protoplasm. The thickening of protoplasm is more characteristic of the maturation phase, not the elongation phase.
- **Conclusion**: This option is **incorrect**.

5. **Analyzing Option IV: New Cell Wall Deposition**:
- As cells elongate, new cell wall material is indeed deposited to accommodate the increased size of the cell. This is essential for maintaining the structure of the cell.
- **Conclusion**: This option is **correct**.

6. **Final Evaluation**:
- Based on the analysis, the correct characteristics during the elongation phase are:
- I. Increased vacuolation (Correct)
- II. Increased cell enlargement (Correct)
- III. Increase in thickness of protoplasm (Incorrect)
- IV. New cell wall deposition (Correct)
- Therefore, the correct answer is **Option 4: I, II, and IV are correct**.