Ascent of sap mainly depends upon

Options

A. Forces of cohesion
B. Forces of adhesion
C. Suction pressure
D. All of these

Answer

### Step-by-Step Solution

1. **Understanding Ascent of Sap**:
- The ascent of sap refers to the upward movement of water and nutrients from the roots to the rest of the plant.
- This process primarily occurs in the xylem tissue.

2. **Direction of Movement**:
- The movement of sap is against gravity, meaning it travels upward through the plant.

3. **Factors Influencing Ascent of Sap**:
- The ascent of sap depends on several forces:
- **Cohesion**: This is the force of attraction between water molecules, which helps them stick together.
- **Adhesion**: This is the force of attraction between water molecules and the walls of the xylem vessels, which helps the water to climb up the vessels.
- **Suction Pressure**: This is a crucial factor that creates a negative pressure in the xylem, helping to pull water upward against gravity.

4. **Identifying the Main Factor**:
- While cohesion and adhesion play important roles, the main driving force for the ascent of sap is suction pressure.
- Suction pressure is generated due to transpiration (the loss of water from the leaves), which creates a negative pressure that pulls water upward from the roots.

5. **Conclusion**:
- Therefore, the ascent of sap mainly depends on **suction pressure**.