Water column does not rupture during ascent in tracheary elements due to

Options

A. Weak gravitationl pull
B. Tranpiration pull
C. Lignified thick walls
D. Cohesion and adhesion

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks why the water column does not rupture during its ascent in tracheary elements (xylem vessels) of plants.

2. **Analyzing the Options**:
- **Weak Gravitational Pull**: This option suggests that a weak gravitational pull prevents the rupture of the water column. However, gravity acts downwards, and even a weak pull could potentially lead to the water column collapsing. Therefore, this option is incorrect.

- **Transpiration Pull**: This is the process where water evaporates from the leaves, creating a negative pressure that pulls water upward from the roots through the xylem. This pull is significant in maintaining the integrity of the water column and preventing it from breaking. Thus, this option is likely correct.

3. **Considering Other Forces**:
- **Cohesion and Adhesion**: These forces also play a role in maintaining the water column. Cohesion refers to the attraction between water molecules, while adhesion refers to the attraction between water molecules and the walls of the xylem vessels. These forces help in keeping the water column intact, but they are not the primary reason for preventing rupture during ascent.

- **Surface Tension**: This is another factor that contributes to the stability of the water column, but again, it is not the main reason for preventing rupture.

4. **Conclusion**: Based on the analysis, the main reason the water column does not rupture during ascent in tracheary elements is due to the **transpiration pull**. Therefore, the correct answer is option number 2.

### Final Answer:
The water column does not rupture during ascent in tracheary elements due to the transpiration pull.

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