Which of the following is not part of the transpiration cohesion-adhesion theory of the ascent of xylem sap?

Options

A. A) The evaporation of water from the mesophyll cells. which initiates a pull of water molecules from neighbouring cells and eventually from the tracheids.
B. B) The transfer of this pull from one water molecule to the next due to the cohesion caused by hydrogen bonds.
C. C) The hydrophilic walls of the narrow tracheids and vessels that help to maintain the column of water against the force of gravity
D. D) The use of proton pumps to create membrane potentials that facilitate the accumulation of mineral ions.

Answer

To solve the question regarding which option is not part of the transpiration cohesion-adhesion theory of the ascent of xylem sap, we can analyze each option step by step.

### Step-by-Step Solution:

1. **Understanding Transpiration Cohesion-Adhesion Theory**:
- This theory explains how water moves from the roots to the leaves in plants. It involves three main processes: transpiration (evaporation of water from plant surfaces), cohesion (attraction between water molecules), and adhesion (attraction between water molecules and the walls of xylem vessels).

2. **Analyzing Each Option**:
- **Option A**: "The evaporation of water from the mesophyll cells which initiates a pool of water molecule from neighboring cells and eventually from the trachea."
- This describes transpiration, which is a key part of the theory. **(Part of the theory)**

- **Option B**: "The transfer of this pool from one water molecule to the next due to the cohesion caused by hydrogen bonds."
- This describes cohesion, which is also a fundamental aspect of the theory. **(Part of the theory)**

- **Option C**: "The hydrophilic wall of the narrow tracheids and vessels that help to maintain the column of water against the forces of gravity."
- This describes adhesion, which helps water to stick to the xylem walls, preventing the column from breaking. **(Part of the theory)**

- **Option D**: "Use of proton pump to create membrane potentials that facilitate the accumulation of mineral ions."
- This describes a process related to nutrient uptake and does not pertain to the movement of water in the xylem. **(Not part of the theory)**

3. **Conclusion**:
- Based on the analysis, **Option D** is the correct answer as it does not relate to the transpiration cohesion-adhesion theory of the ascent of xylem sap.

### Final Answer:
**Option D**: Use of proton pump to create membrane potentials that facilitate the accumulation of mineral ions.

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